One of the common features of an epic is the "fabulous loci" for the hero to visit. Fantasy novels can have some loci that are quite pretty or terrifying, but science fiction has some that will make your jaw hit the floor. Try comparing the land of Fairie with a ring around a sun with a radius of an entire astronomical unit and a livable surface area of three million times Terra.

Some of them are even from reality, e.g., Saturn's Rings.

This entire page counts as backgrounds and plot ideas for science fiction authors.

The Lost Spaceship

A nice standard location is a famous mysterious lost spaceship, especially if it is full of treasure or something. This is commonly part of a treasure hunt story, with the protagonists searching for the ship in order to discover the Dread Secret of its disappearance. In many stories the lost spaceship also has the answer to some old mystery, typically something that the political powers that be would prefer to remain secret because it would shake things up. Examples include The Ghost Line: The Titanic of the Stars by Andrew Neil Gray, J.S. Herbison, All Cats Are Gray by Andre Norton, and A Talent for War by Jack McDevitt.

And in others it turns out that there is a blasted good reason the ship is lost, because there is Something Awful lurking inside. The protagonists who discover the ship are quick to regret it. Examples include Alien, Event Horizon, The Dark Side of the Moon, and ST:TOS Space Seed; which contain respectively the Xenomorph, a Gate To Hell, The Devil and Khan Noonien Singh.

If there are a huge number of lost spaceship, this turns into a Sargasso of Space.

If this is more a Mary Celeste situation (protagonists are not looking for a ship but unexpectedly encounter a recently deserted ship with hot food still on plates), it is called a Ghost Ship. Examples include Polaris by Jack McDevitt, ST:TOS The Tholian Web, The Black Hole, and 2010: Odyssey Two. In the movie Sunshine the Icarus I initially appears to be a Ghost Ship but it is actually a ship with Something Awful lurking inside.

If the ship has been traveling for centuries (sometimes containing a miserable crew that cannot escape), it is called a Flying Dutchman. Examples include Firebird by Jack McDevitt and Andromeda "The Mathematics of Tears".


For I was there, right in the Rigel Royal, when it all began on the night that Cliff Moran blew in, looking lower than an antman’s belly and twice as nasty. He’d had a spell of luck foul enough to twist a man into a slug-snake and we all knew that there was an attachment out for his ship. Cliff had fought his way up from the back courts of Venaport. Lose his ship and he’d slip back there—to rot. He was at the snarling stage that night when he picked out a table for himself and set out to drink away his troubles.

However, just as the first bottle arrived, so did a visitor. Steena came out of her corner, Bat (the cat) curled around her shoulders stole-wise, his favorite mode of travel. She crossed over and dropped down without invitation at Cliff’s side. That shook him out of his sulks. Because Steena never chose company when she could be alone. If one of the man-stones on Ganymede had come stumping in, it wouldn’t have made more of us look out of the corners of our eyes.

She stretched out one long-fingered hand and set aside the bottle he had ordered and said only one thing, “It’s about time for the Empress of Mars to appear again.”

Cliff scowled and bit his lip. He was tough, tough as jet lining—you have to be granite inside and out to struggle up from Venaport to a ship command. But we could guess what was running through his mind at that moment. The Empress of Mars was just about the biggest prize a spacer could aim for. But in the fifty years she had been following her queer derelict orbit through space many men had tried to bring her in—and none had succeeded.

A pleasure-ship carrying untold wealth, she had been mysteriously abandoned in space by passengers and crew, none of whom had ever been seen or heard of again. At intervals thereafter she had been sighted, even boarded. Those who ventured into her either vanished or returned swiftly without any believable explanation of what they had seen—wanting only to get away from her as quickly as possible. But the man who could bring her in—or even strip her clean in space—that man would win the jackpot.

“All right!” Cliff slammed his fist down on the table. “I’ll try even that!”

Steena looked at him, much as she must have looked at Bat the day Bub Nelson brought him to her, and nodded. That was all I saw. The rest of the story came to me in pieces, months later and in another port half the System away.

Cliff took off that night. He was afraid to risk waiting—with a writ out that could pull the ship from under him. And it wasn’t until he was in space that he discovered his passengers—Steena and Bat. We’ll never know what happened then. I’m betting that Steena made no explanation at all. She wouldn’t.

It was the first time she had decided to cash in on her own tip and she was there—that was all. Maybe that point weighed with Cliff, maybe he just didn’t care. Anyway the three were together when they sighted the Empress riding, her dead-lights gleaming, a ghost ship in night space (dead-lights signal "danger, stay out!").

She must have been an eerie sight because her other lights were on too, in addition to the red warnings at her nose. She seemed alive, a Flying Dutchman of space.

(ed note: and yes, there is Something Awful on board)

From ALL CATS ARE GRAY by Andre Norton (1953)

But Van Rycke was not just a machine of facts and figures, he was also a superb raconteur, a collector of legends who could keep the whole mess spellbound as he spun one of his tales. No one but he could pay such perfect tribute to the small details of the eerie story of the New Hope, the ship which had blasted off with refugees from the Martian rebellion, never to be sighted until a century later — the New Hope wandering forever in free fall, its dead lights glowing evilly red at its nose, its escape ports ominously sealed — the New Hope never boarded, never salvaged because it was only sighted by ships which were themselves in dire trouble, so that "to sight the New Hope" had become a synonym for the worst of luck.

Then there were the "Whisperers", whose siren voices were heard by those men who had been too long in space, and about whom a whole mythology had developed.

Van Rycke could list the human demi-gods of the star lanes, too. Sanford Jones, the first man who had dared Galactic flight, whose lost ship had suddenly flashed out of Hyperspace, over a Sirius world three centuries after it had lifted from Terra, the mummified body of the pilot still at the frozen controls, Sanford Jones who now welcomed on board that misty "Comet" all spacemen who died with their magnetic boots on. Yes, in his way, Van Rycke made his new assistant free of more than one kind of space knowledge.

From SARGASSO OF SPACE by Andre Norton (1955)

Pocket Universe

This is when you find a "door" or "hole" in the space-time continuum that transports you to another universe, generally smaller that our universe. Otherwise the other universe is cannot be detected from our universe. The laws of physics may or may not be identical to ours. Known as Pocket Universe or Pocket Dimension. An example is the Elysia dimension from the ST:TAS episode THE TIME TRAP and The Way in Greg Bear's EON (1985). There is a virtual-reality/cyberpunk version in Walter Jon Williams' IMPLIED SPACES (2008).

Sometimes the pocket universe is very small, like only several times the diameter of a planet. These often contain a Sargasso of Space.

Sometimes the door is associated with an object, leading to the illusion that the object is "bigger on the inside than the outside." An example is the TARDIS from Doctor Who. Another is the bag of holding from Dungeons & Dragons (which may have been inspired by the "overpocket" from Robert Silverberg's NIGHTWINGS (1968)). Also the subspace storage pocket used by Transformers. Not to mention a Flerken's stomach.

And sometimes the door is invisible. There is no warning when the starship blunders into the door, it only becomes visible to the hapless starship and only when it is too late to escape.


Another Dimension that is not so "other", Pocket Dimensions are spaces that are too small or too easily accessible to be truly considered a separate dimension and are referred to as a small extra pocket of space that is attached to our own. Much like an actual pocket, they are often used for some extra space where you can get things Bigger on the Inside. A Speculative Fiction favourite, the uses are plentifold. Storage for a Bag of Holding, hiding places, transportation, an explanation for physics-defying superpowers: a Pocket Dimension can do them all. Can't make julienne fries though.

Also can serve as a (sometimes unstable) Small, Secluded World with its own ecosystem and lifeforms. This is a quite handy place for keeping some nasty lurksome monsters; it lets them be very alien and make intermittent contact.

See also Just One Second Out of Sync which is often exactly the same but explained in terms of a temporal fashion than a spatial one. Not to be confused with a Palm OS game of the same name.

(ed note: see TV Trope page for list of examples)


The Warbots at Critter's Gateway ca. 7200

While all manner of advances were made in the warbots since the Peolanti wars, and several smaller wars were fought with them, there were no significant changes in their appearance until the discovery of Critter’s Universe.

Eleven light-years from Antares there was a small dust cloud which emitted a healthy amount of radio waves. These clouds were not uncommon, so little attention beyond marking it as a navigation hazard was paid to it. Then Jorj Critter, a prospector looking for natural rubies, flew into it. It turned out to be an area in which space had formed a side-bubble, where physical laws were somewhat different. The periodic table of Critter’s Universe held but four elements, a solid, a gas, a plasma and a liquid, promptly dubbed Earth, Air, Fire and Water. While perfectly stable in their own little universe, subjecting any object made of them to our physical laws caused destabilization of the Fire content, which caused the whole mass to oscillate into pure energy. Since Critter found it was very simple to control this attempt to justify itself to our physical laws, he told Andrew the Meditator the current Pantocrator of Antares, about this new power source.

Critter’s Universe, which is only about a hundred light-years in diameter, did coexist with a large section of the Terran Organization of Star States, who, having learned about this, decided they should own it. The TOSS went to war with Antares, the focal point of the war being around the little nebula, Critter’s Gateway. TOSS battlewagons and mobile asteroids faced over a million warbots of Antares and soon discovered that they could not possibly defeat such a swarm of tiny adversaries. The TOSS never got within a billion miles of the actual gateway and would have lost regardless of whether or not the League pulled another trick from a hat.

For several thousand years, Green Companion of Antares had been known as a tempestuous stellar bastard, constantly filling all space around it with radiation clouds and fouling up communications. It had several dozen planets which could be very pleasant if the sun were calmed down somewhat, so the Hubley University extension at Antares Vert, had been established in 6200 to seek ways of controlling the star. Shortly before the war, they found the first major advance of macromechanics, how to blow a star into a nova. It worked as well on stable, main-sequence stars as the huge, wasteful monsters like Rigel, upon which it was demonstrated. The TOSS now realized that the League could seed their stars through Critter’s Universe and blow them all to perdition before anything could be done. Hastily withdrawing their forces from the Gateway, the TOSS began cultivating good feelings with forced urgency.

The warbot used at Critter’s Gateway was a very capable little vessel, as much spaceship as groundcraft. The soldier, sitting in lotus, was freed of his helmet. From an amorphoid plate at the top of the warbot, he could extrude a battleraft or a head, from two plates at the side he could extrude any of an arsenal of two hundred weapons. The circuitry of these amorphic devices was mostly magnetic and gravitic domains, which could not be altered by any amount of twisting and contorting, so they could be extruded whenever needed, otherwise remaining placid as a puddle of quicksilver in their storage tanks.

Antares, while again the little empire of space, was also the most powerful, for they had over a million of these things strutting back and forth through space.

From THE WARBOTS by Larry S. Todd (1968)

Elysia was a small alternate universe, a parallel time continuum, that periodically touched the prime universe in the Delta Triangle region of the galaxy. Elysia was more aptly described by Devna, as "a pocket in the garment of time." The collisions between the two alternate universes produced time warp vortexes in the time barrier between the universes. The warps allowed passage from one side to the other at high warp speed.

Elysia was governed by the Elysian Council. Its "starship graveyard" contained all of the ships lost in the Delta Triangle over the millennium preceding the arrival of the USS Enterprise. While time passed at the same rate, the effects of time, like aging, occurred at an extremely slow rate in Elysia relative to the outside universe. All acts of violence were forbidden in Elysia, and were stopped by the members of species with psionic powers. Captain James T. Kirk noted that "Elysia is, in many respects, a perfect society. But with all its virtues, it is not home. And home, with all its faults, is where we prefer to be." (TAS: "The Time Trap")

From the Memory Alpha entry for ELYSIA


The Slow Zone, the Dandelion Sky or the Hub is the location on the other side of the Ring. It's a black, starless space approximately one million kilometers across, with 1373 individual Ring wormholes in an enormous sphere around it. Ring Station sits in the middle of the slow zone. The actual location of the slow zone in space, or whether it is connected to the universe other than through wormholes, is unknown.

The slow zone was named for its absolute speed limit of six hundred meters per second. Any object with non-zero invariant mass moving faster than this limit is locked down by an inertial dampening field, and then begins to move towards the central Ring Station, forming a ring around it. Light still acts normally and adheres to the speed of light, but radiation made up of larger particles like alpha and beta radiation does not exist inside the slow zone.

For more information about the events at this location, see Slow Zone Incident.


  • The "speed limit" is described as an active defense mechanism of the Ring Station in Abaddon's Gate rather than a fundamental change in constants of nature. "The speed limit grips the hull of the ships but anything inside is unaffected." This effect is used as a key plot elements throughout Abbadon's Gate. Bullets fired from weapons behave normally inside ships. A grenade fired by a Martian marine on Ring Station though "comes to a halt and drops to the ground centimeters from the barrel." When the speed limit is dropped, crew and passengers are killed or injured due to the sudden deceleration of the ships hulls.
  • Initial readings also suggest that the background microwave radiation in the Slow Zone is older than the Big Bang.
From the Expanse Wiki entry for SLOW ZONE (BOOKS)

Pocket Dimension: Alas, outside virtual reality, this seems to require basement universes (requires very high-energy physics, being worked on) or dimensional transcendence (requires emergent ontotechnology, also being worked on).

Being worked on very enthusiastically by starship manufacturers, I note, because holy mother of crap what would being able to keep your remass in a pocket dimension do for your mass ratio!

(Let’s hope that the mass of the contents inside doesn’t seamlessly translate to the mass of the dimension “mouth” outside…)

Sargasso of Space

In old pulp science fiction there is a long history of taking a dramatic and comfortable metaphor and transporting it intact into the outer space environment. Generally the author has to savagely pound a square peg into a round hole, with regrettable results. The classic horrible example is deep space fighter aircraft.

Most pulp falls for the old Space Is An Ocean fallacy along with the related misconceptions.

Many pulp writers figured they were the first to have the bright idea of transplating the colorful legend of the dreaded Sargasso Sea into science fiction. A deadly area of space that somehow traps spaceships who venture too close, only to join the deadly graveyard of lost ships. And not just human ships, a couple stories mention humans discovering wrecks of unknown alien spacecraft mixed in with the conventional ships. The graveyard typically contains everything from recent ships all the way back to historical ships dating to the dawn of space flight.

Some stories populate the graveyard of dead ships with castaways. Who will probably be interested in looting your ship of any supplies it contains.

The original legend dates back to when line-of-sight was limited to the horizon, so a sailing vessel poking at the edge of the sargasso could not see the interior. Not without being caught, that is.

With the invention of radar and the realization that there ain't no horizon in space, writers realized they'd have to make the space sargasso sea more invisible. Usually they'd add on the legend of the Bermuda Triangle in the form of an intermittent "hole in space" leading to a pocket universe. Some kind of wormhole or stargate that would transport the hapless spacecraft to a graveyard of lost ships safely out of sight.

In some scifi stories, the sargasso was the location of a huge space battle so it is littered with shot-up warships. If the governent that has jurisdiction over the area does not want to be stuck with the huge bill for cleaning up the mess, they will designate it as a "graveyard". Generally a small sentry task force will be patrolling the sargasso, to ensure that nobody sneaks into the ships in order to desecrate the dead bodies and/or try and salvage missiles with nuclear warheads or something.

Obviously this is highly unlikely to happen in the real world. But it sure is romantic, in a sci-fi pulp fiction sort of way.

THE SARGASSO OF SPACE by Edmond Hamilton (1931)
The sargasso here is apparently the Neptune-Sol L5 point. Disabled spacecraft who drift into the point will be trapped, which is sort of true. The author does not explain why this is not true of the L4 and L5 points of every single planet in the solar system. He calls the graveyard of lost ships the "wreck-pack", and the gravitational attraction of the wrecks keep ships from drifting out.
CALLING CAPTAIN FUTURE by Edmond Hamilton (1940)
In this novel, the sargasso of space is created by ether-currents in the luminiferous aether. The latter is a concept that was disproved by Michelson and Morley in 1887, but most of the readers didn't know that. The ether-currents form sort of a one-way whirlpool which sucks hapless spacecraft into the graveyard of lost ships trapped in the eye of the storm. Captain Future escapes by cannibalizing engine and atomic fuel from the other derelict ships, an idea that apparently didn't occur to any of the prior castaways. He has a side adventure when he stumbles over an alien spacecraft full of aliens in suspended animation. The "adventure" part comes in when Captain Future discovers the octopoid creatures are space vampires and they start to wake up.
SARGASSO OF LOST STARSHIPS by Poul Anderson (1952)
Superstition says that the Black Nebula is haunted. Certainly strange things happen to hyperdrive starships who venture too close. Things like hallucinations, ghostly whispering voices ("Spaceman, go home. Turn back, adventurer. It is death."), electrical gear malfunctioning. Many dissappear, so prudent ship captains give the Nebula a wide berth. The cause of all this is an ancient race of Elf-like psionic aliens living on a planet near the Nebula's center.
SARGASSO OF LOST CITIES by James Blish (1953)
The spacegoing cities of CITIES IN FLIGHT gather in the sargasso for reasons that have less to do with physics and more with economics. The antigravity Okie cities are sort of the migrant laborers of the galaxy. The stellar currency is based on germanium, some idiot figure out how to synthesize it and inadvertenly obliterated the economy of the entire galaxy. Since everybody is now broke, the flying cities cluster in what is basically an interstellar hobo jungle.
SARGASSO OF SPACE by Andre Norton (1955)
The valiant free traders of the good ship Solar Queen obtain the trading rights to the dead planet with the cheery name "Limbo". When they visit they learn the planet has a still-working thousand-year-old alien installation created by forerunners which can grab passing spacecraft with a tractor beam and crash them onto a valley containing the graveyard of lost ships. As it turns out a crime syndicate wants to utilize the installation for fun and profit, so hilarity ensues.
THE GRAVEYARD OF SPACE by Milton Lesser (1956)
The graveyard of space is a ball of dead spacecraft orbiting in the asteroid belt. Apparently it started as a small sphere of neutronium or other dense material. As derelict ships stuck to it by gravitational attraction the total gravity grew. It is only a menace to ships with broken engines or no fuel. The planetary governments keep talking about blasting it and salvaging the metal but can never agree on the details. Our heroes accidentally crash into it, breaking their Gormann series eighty radarscope. They cannot escape without one. So they start investigating the ships of the graveyard hoping to scavange a replacement. That's when they discover the hard way that anybody trapped in the graveyard will have to resort to cannibalism in order to survive, and who will treat them like the unexpected arrival of fresh meat on the hoof.
THE STARS MY DESTINATION by Alfred Bester (1956)
The protagonist Gulliver Foyle encounter the Sargasso Asteroid, a body in the main asteroid belt built entirely from the hulks of abandoned spaceships.
TIME TRAP episode of Star Trek Animated (1973)
The Starship Enterprise and a Klingon battle cruiser become trapped in the "Delta Triangle", an almost not disguised reference to the Bermuda Triangle. A hole in space drops them in to a pocket universe answering to a sargasso sea, and packed with the graveyard of lost starships. They find the centuries-old Starship Bonaventure, first starship with warp drive. But all the crew of all the ships are still alive, since people age slowly inside the sargasso, and antimatter lasts a long time. The Enterprise and the Klingon escape by hot-wiring their engines together, though true to form the dastardly Klingons try last minute treachery.
DRAGON'S DOMAIN epsiode of Space 1999 (1975)
In a flashback, Tony Cellini remembers when he was on the Ultra Probe to the newly discovered planet Ultra. Nearby they encounter a cluster of drifting abandoned alien ships. They discover why the ships are abandoned when an unconvincing octopoid monster with one eye and a firey maw materializes and starts to eat the crew.
THE METAMORPH epsiode of Space 1999 (1976)
Mentor of the planet Psychon needs to abduct sentient beings so he can drain their mental energy into his diabolical biological computer. He uses magnetic force to drag down to the planet any spacecraft that pass by, creating a large graveyard of lost ships nearby his operation.
DEADLY REUNION (Star Wars Comic) by Archie Goodwin (1981)
The Graveyard of Lost Ships was a collection of starships which were drawn into orbit around a collapsed dwarf star by Doctor Arakkus. The Graveyard consisted of five interconnected rings of ships all of which had been lured to the Graveyard with distress calls, in an attempt to make others suffer as he had suffered. The ships were trapped in the Graveyard by the gravitational pull of the dwarf star. Incapable of escaping its grasp, the ships slowly began to plunge into the star, while most of the crews went insane and committed suicide. But Han Solo, Luke Skywalker, and Chewbakka put a stop to this.
MÖBIUS DICK episode of Futurama (2011)
The Planet Express makes the mistake of taking a short-cut through the Bermuda Tetrahedron (an almost not disguised reference to the Bermuda Triangle) and land in a graveyard of lost spacecraft. The graveyard includes many media science fiction ships as joke references, including Discovery One from 2001 A Space Odyssey, Oceanic Airlines Flight 815 from Lost, the Satellite of Love from Mystery Science Theater 3000, the Jupiter II from Lost In Space, the ship from Josie and the Pussycats in Outer Space, the ship from the album covers of Electric Light Orchestra and Boston, an Apollo Lunar Module, an Apollo Command and Service Module, and Skylab.
In the Traveller RPG, most of the population lives on the habitable planet Garoo. However, for undiscovered reasons, starships passing within a couple of parsecs who suffer a misjump tend to materialize near the the sixth planet "Graveyard" and immediately crash onto the surface. There was a small community of scavengers living on the planet who took advantage of the situation. These have been mostly removed from the planet. Nowadays there is an Imperial research station studying the phenomenon, and a naval rescue station set up to intercept and rescue misjumped ship before they collide with the planet.
In the Traveller RPG, several large battles of the Fifth Frontier War were fought here. The shattered warships were dragged to the Warship's Graveyard by space tugs to prevent them being navigational hazards. The area has been designated a war grave by both sides in the war. It is patrolled to prevent all but licensed salvage operatives from entering.

      "The dead area," Crain told them, "is a region of space ninety thousand miles across within Neptune's orbit, in which the ordinary gravitational attractions of the solar system are dead. This is because in that region the pulls of the sun and the outer planets exactly balance each other. Because of that, anything in the dead-area, will stay in there until time ends, unless it has power of its own. Many wrecked space-ships have drifted into it at one time or another, none ever emerging; and it's believed that there is a great mass of wrecks somewhere in the area, drawn and held together by mutual attraction."
     "Wreck-pack in sight ahead!"
     "We've arrived, anyway!" Kent cried, as he and Crain hastened up into the pilot house. The crew was running to the deck-windows.
     "Right ahead there, about fifteen degrees left," Liggett told Kent and Crain, pointing. "Do you see it?"
     Kent stared; nodded. The wreck-pack was a distant, disk-like mass against the star-flecked heavens, a mass that glinted here and there in the feeble sunlight of space. It did not seem large, but, as they drifted steadily closer in the next hours, they saw that in reality the wreck-pack was tremendous, measuring at least fifty miles across.
     Its huge mass was a heterogeneous heap, composed mostly of countless cigar-like space-ships in all stages of wreckage. Some appeared smashed almost out of all recognizable shape, while others were, to all appearances unharmed. They floated together in this dense mass in space, crowded against one another by their mutual attraction.
     There seemed to be among them every type of ship known in the solar system, from small, swift mail-boats to big freighters. And, as they drifted nearer, the three in the pilot-house could see that around and between the ships of the wreck-pack floated much other matter — fragments of wreckage, meteors, small and large, and space-debris of every sort.
     "Lord, who'd have thought there were so many wrecks here!" Kent marvelled. "There must be thousands of them!"
     "They've been collecting here ever since the first interplanetary rocket-ships went forth," Crain reminded him. "Not only meteor-wrecked ships, but ships whose mechanisms went wrong—or that ran out of fuel like ours—or that were captured and sacked, and then set adrift by space-pirates."
     In those hours Kent and Crain and all in the ship watched with a fascinated interest that even knowledge of their own peril could not kill. They could see swift-lined passenger-ships of the Pluto and Neptune runs shouldering against small space-yachts with the insignia of Mars or Venus on their bows. Wrecked freighters from Saturn or Earth floated beside rotund grain-boats from Jupiter.
     The debris among the pack's wrecks was just as varied, holding fragments of metal, dark meteors of differing size—and many human bodies. Among these were some clad in the insulated space-suits, with their transparent glassite helmets. Kent wondered what wreck they had abandoned hastily in those suits, only to be swept with it into the dead-area, to die in their suits.

From THE SARGASSO OF SPACE by Edmond Hamilton (1931)

(ed note: our heros are in one of thirty-odd starships that managed to escape the supernova that obliterated their home planet. The starships went in all directions to maximize the chance of finding a habitable planet. The Javelin had already found one planet which proved to be hideously unsuitable. After a decade they find another...)

      "The three planets bracketed by these two extremes are all livable, and in fact the spectroscope shows that life has arisen on all three. The fourth planet outward from the sun, a world 9,000 miles in diameter with one very large moon and two small ones, is particularly verdant, and close inspection shows that both the planet and the large moon were in fact occupied at one time. The lunar installation is a featureless metal dome. The planet can be seen to bear many large stone and metal artifacts suggesting cities, now obviously quite silent and deserted. Pending exploration, their age, origin and fate remain conjectural.
     "We are not yet able to say upon what basis our computer selected this extraordinarily promising system, but hope to accumulate more data after planetfall. Stand by."

     The hammer fell. As the Javelin began to settle complacently into the outermost reaches of the atmosphere of that abandoned, incredibly rich planet, the smooth, blown-steel, pilot-fish shapes of the blind little ships came raining down around her out of the blackness, spitting needles of white fire. The computer rang all its bells at once, radio heat red orange yellow green blue indigo violet ultra-violet X-ray and panic, but it was too late. Above the bubble ships which were seeing to it that the Javelin continued to go down, turret-bumpy forts as big as small moons crashed into orbit out of nothingness, indifferently forcing the entire metrical frame of local space-time to bear their malignant tumorous masses with groans profound enough to be heard, should anyone with ears for gravitational waves be listening, almost to the center of the galaxy.
     The computer yelled its mechanical horror so loudly in the control barrel of the lavelin that it was almost impossible to think. After a brief moment of fury and bafflement, Ertak cut its power; and then, for thirty seconds of ringing, desperate silence, he turned his back on the barrel and pressed his temples with the heels of his hands.
     "We are fordone," he said at last in a high, white voice. 'We will maintain our landing trajectory. We have no other choice. Ailiss!"
     "Great Ghost. Yes, Director."
     "Try to raise someone out there. Find out what they want; try to convince them that we're harmless. They've got us—there's no other way out."
     There was no doubt about that. The hull of the lavelin was banging continuously with the admonitory small shot from the bubble ships, obviously not intended to wound the great clumsy interstellar vessel much, but only to see to it with a fusillade of whipcracks that she came to ground conveniently near her proper cow-barn. She could no longer see the landing place she had picked for herself; suddenly the quiet atmosphere into which she had been settling was aroil with black storms, blinking and bursting with gigantic, jagged lightning-bolts.
     'No," Ailiss said, in a hoarse whisper. "Oh, no."
     The beautiful creature on the screen smiled at her, but without mercy.
     "And why not?" he said, in a voice as deep and rich as that of an organ. "You cannot say no to us. You never could. You were stupid to try; and now ies far too late. Too bad—anywhere else, you might have gotten away with it."
     As Ailiss swallowed and attempted to muster an answer, he burst into a peal of musical, glistening black-and-white laughter. There was no humor in it, though there was a great deal of joy: it was the amusement of a demon, part delight, part calculation, and part the compulsive whicker of insanity.
     While the laughter died away, they had time to realize that this tall man-thing without lashes, brows or hair which glittered at them from the screen like volcanic glass spoke their language as fluently as through he had been born to it—and as contemptousIy as though he had picked it up entirely just yesterday afternoon.
     "You're making a mistake," Ailiss said, with the sudden prim severity of a schoolteacher. "We're not doing you any harm."
     "No, indeed. Nor will you. We've been listening to you talk to yourselves ever since your probe picked us up; we know what's on your mind—and we know about your other starships waiting outside. We mean to make an example of you. This system is ours."
     "They may wind up making an example of you," Ailiss said, seizing instantly upon the slight apparent error. "For that matter, we are not as helpless as you think. We could very well plant nuclear bombs in a good many of your cities before we're forced down."
     "The cities are empty," the creature said indifferently. "Do you know why you didn't detect us until now? We evacuated this planet completely when we heard you coming, and shut down electromagnetic activity throughout our system. If your main force looks too strong for us, why then we won't be found; and if it isn't—!' Symbolically he cut his throat, with a gesture an the more shocking for its complete—and completely spurious—familiarity.

     Ertak, out of sight of the, screen, beckoned to Jorn, motioning for silence. Jorn walked over to him, and tried to understand his pointing finger and odd gestures. Kambfin understood first, and once he fumblingly began to carry out the action, Jorn could see what was wanted: a jury-rigged "take-off" sequence without benefit of the computers. It looked like sheer suicide, but there was no time to argue; he could no more successfully rig such a thing than Kamblin could. He buzzed crew"s quarters for the armorer; she seemed to arrive almost before he took his finger off the button. She looked once, nodded once, and got to work.
     "I can see that you don't have an interstellar drive of your own," Ailiss' voice went on. "You'd be better off dealing with us, instead of shooting at us. We may have a good many other things you might want."
     "An interstellar drive is of no use to us," the creature said. "And if it were, we would invent it ourselves. I demean myself by talking to a race that could make such an offer. Death and destruction to you all."
     The screen went dark. Ailiss wrung suddenly trembling hands.
     "Ailiss, no time now for shock reactions," Ertak said in a voice as bleak as lava. "Come here and see what we're doing—and don't say anything aloud about it. I don't know whether our friend can overhear us when we're off the air or not, but I don't want to take any chances. Do you understand this rig?"
     "Mmmm... yes, Director."
     "All right, it's your job to run it, understand? just as you would a more conventional thing of its kind. Pick your own, uh, target, and don't stint—do you follow me?"
     "I know all the 'buts' just as well as you do," Ertak said. "We've got no time for them. You've got fifteen seconds to familiarize yourself with the apparatus, starting now." He snatched up a microphone. "To ALL HANDS. THIS IS BLUE WARNING FOUR, OTHERWISE UNSPECIFIED. SEARCH YOUR MEMORIES. SIGNAL BLUE IN TEN SECONDS. SIGNAL BLUE IN TEN SECONDS."
     Those ten seconds seemed preternaturally quiet to Jorn, despite the screaming of the atmosphere and the clangor of the missiles against the hull. Five… four… three… two… one…
     With a rasping roar from the drive, more thunderous and ugly than any sound it had ever made before, the Javelin rolled on her axis and clawed skyward, on full emergency acceleration.

     The nearest fort got off a shot at her as she passed, already doing 200 miles per second and building more velocity every instant. The shot was a clean missluckily, for a few thousand miles to starboard-and-rear some metallic bit of meteoric trash triggered its proximity fuse and it blossomed out into a megaton fusion explosion.
     But from now on, for a while, the Javelin would be an increasingly better target. If the creatures had a drive fast enough to enable them to colonize all their planets economically, furthermore, there would still be a considerable gauntlet to run.
     The gabble of venom and fury spewing after them by radio did not suggest that the creatures would simply be glad to see them go. The ranging shots were coming closer— But in fact the battle was effectively over. Had the fifth planet not been on the other side of the sun at the time, the outcome might have been different; but as events actually fell out, there was only a stern chase, in which the Javelin proved to have the advantage all the way. The ranging shots fell farther and farther behind; and then, finally, they stopped.
     "Radio silence until we pass the light barrier," Ertak ruled, mopping his brow. "And we'll keep the computer off, too. I strongly suspect that those devils could overhear it thinking, if they could pick up its probes from three light years out—and if it is in some sort of contact with computers in the other ships, so much the worse. After we pass light speed, we'll risk using my communicator to pass the word, but not before."
     He turned toward his quarters, steadying himself with one band against a bulkhead; suddenly he seemed to be all gone at the knees. Jorn could well understand why; he was grateful that be himself was already sitting down.
     Then, surprisingly the Director turned back.
     "Masterly piloting, Ailiss," he said. "And not as rough as I expected; but Doctor, you'd better check around for injuries. Jorn, you'd better find out where we're headed."
     And then be vanished.
     Her drivers still snarling under the maximum emergency overload, the Javelin raced outward from her second defeat.
     And this one, Jorn sensed dimly, was crucial. It would never be completely forgotten; eventually, if any of them survived, it might retreat into the mists of mythology, but it could never be expunged from the racial memory.
     It was one thing to be driven off a verdant world by blind natural forces ... and quite another to be scourged away with whips and contempt, by a people very like their own—whose last words had been a promise of undying hatred for so long as any member of either race remained alive.
     It was a heavy blow.

     "Ailiss tells me you were in to see the Director this morning. Any news?"
     "No good news," Kamblin said, twisting his mouth wryly. "I'm afraid he's not going to be with us much longer."
     "I suppose you're right, but it's hard to believe. I thought he'd last forever. My, he's younger than you are... and he's had these fits of being in isolation before. He always comes out, when there's any real need for him."
     "He's a sick man," Kamblin said heavily. "Sick in his mind. This business with the devils... well, of course, you don't know the whole story."
     I was there," Jorn said, a little huffily.
     "That's not what I mean. I don't suppose there's any harm in your knowing about it now. You see, those creatures were never there at all."
     "Never there...! Excuse me, Dr. Kamblin, but they made some remarkably real dents in the Javelin."
     "I know. Let me begin at the beginning. Didn't it strike you that that creature was more than a little insane, going to such lengths to destroy one ship, and refusing even to consider that we might have sornething to offer him? And he was the only one of them we ever saw; he made decisions that only the chief person of the entire system could have made—but under what circumstances would such a personage be in direct command of a fleet? Then there was his claim that they had evacuated a whole planet, in something under six months, just to trap one ship—ours. Not very easy, or very logical either. But he also claimed that they had maintained strict electromagnetic silence from the moment they overheard our computer until the time they jumped us. Tell me, Jorn, is that possible?"
     "Well, with chemical rockets... but then theres communications, logistics ... No, you're right, it isn't possible. No electromagnetics, no evacuation."
     "Very good, now we reach step two: To maintain a high energy civilization, you must have power—lots of it. Yet he claimed that they shut themselves down entirely for six months in order to hide themselves from us; and he said they would do it again if our imaginary 'main body' proved to be too big for them to handle. For how long could they have done that? Supposing this main body had decided to stick around indefinitely? Would the creatures have just remained in hiding, living on roots, until they froze to death? Not very likely."
     "Hmmm. But the electromagnetic silence was perfectly real; we sampled continuously, and never heard a whisper, beyond whatever it was that the computer first picked up."
     "Right," Kamblin said solemnly. "The silence was real; therefore the high-energy civilization was not. You can't shut a high-energy civilization down that far without exterminating it, it's just plain impossible. And if Ertak hadn't cut the power to the computer when we were attacked, we might have found that out in time. That was one of the things the computer was ringing its alarms about; it detected right away that the entire attack was being directed from a single central source—that big metal dome on the large moon. Now it makes sense, you see: you can shut down the energy output of a single installation to a trickle, and shield the trickle, except for detectors; and if the detectors are transistorized they don't make enough noise to be overheard from space.
     "And once we turned the computer back on again and fed the tapes of the attack to it, it immediately identified the broadcast of the creature as coming from the same source. Furthermore, it identified the creature himself as a solidigraph—a construct. So we never really saw even one creature; we saw a synthetic image, and heard a synthetic voice. The computer also says that what was actually doing the speaking—the being with which Ailiss was really talking—was itself a computer."
     "Great Ghost," Jorn whispered. "But, couldn't there have been—"
     "A real such race? Yes, we think so. But there are two more things to be added. While we were in our aborted landing orbit around that planet, we were photographing continuously, as a matter of course; and the pictures show that all the cities over which we passed were in a fairly uniform stage of ruin, Secondly, we passed over the spot which later turned out to be the place where our attackers wanted us to land; and after this matter came up, we examined that site closely.
     "It evidently had been a landing field, a large spaceport, at one time in the distant past. Its completely overgrown now, and you can only see its bare outlines. You can also see two wrecks. One of them is about three hundred years old, if we have interpreted the vegetation around it correctly. It looks rather like the Javelin in general design. The other one is such a ruin that almost nothing can be told about it, except that it's of completely different design. I would like to guess that the more recent of the two might have been a refugee from the Great Nova, but of course, that's just my romantic nature speaking.
     "Given this much, however, we can put the story together. The creature race obviously was real, and it was probably just as proud and hostile as was the ghost of it we encountered—after all, the computer involved had to build its solidigraph and its social attitudes from stored data, it couldn't invent them. Maybe the race was visited by an interstellar squadron once, and was sufficiently panicked to fortify against any such visitor again; so they built the lunar station, equipping it to act the moment it detected an intruder, long before the people themselves could.
     "After a while—who can guess bow long a while?—the computer malfunctioned. It went mad, if you like. It decided that the black race itself was the invader against which it was instructed to act, and it so acted. If each of the two wrecks we saw was a refugee from a separate supernova explosion, as we are, then that race has been dead at least six hundred years, and probably more. The cities are in poor enough shape to support that estimate. But the trap is still there, and it very nearly made us its third victim—or, counting the creature race, its fourth."
     For a while Jorn could think of nothing to say. At last, he found one unanswered question: "So then if we'd just bombed that lunar installation—but how long ago did you find this out? Wasn't there any other ship nearby who could have gone in there and done what we failed to do? It would be easy enough to pretend to walk into the trap, and then hit the lunar station with a fusion salvo—and after that, that whole beautiful system—"
     "Yes, I know," Kamblin said. "That's what's hurting the Director's sanity."

From ...AND ALL THE STARS A STAGE by James Blish (1960)

      (Wyman said) “Dr. Luce, you’re a scientist. I asked you here to set you a scientific puzzle.” His accent was stilted, a mask for his origins. “Did you read about the lithium-7 event? No? A nova-bright object fifteen billion light years away; it lasted about a year. The spectrum was dominated by one element. Doctor, the thing was a beacon of lithium-7.”
     I thought about it. “Fifteen billion years is the age of the Universe. So this object went through its glory soon after the Big Bang.”
     Thin fingers played with coiffed hair. “So, Doctor, what’s the significance of the lithium?”
     “Lithium-7 is a relic of the early Universe. A few microseconds after the singularity the Universe was mostly quagma—a magma of free quarks. Then the quarks congealed into nuclear particles, which gathered into the first nuclei.
     “Lithium-7 doesn’t form in stars. It was formed at that moment of nucleosynthesis. So all this points to an early Universe event. What’s this got to do with me? I hate to disappoint you, Wyman, but this isn’t my field.”
     “Two reasons. First, creation physics. Here we have a precise location where we can be certain that something strange happened, mere moments after the singularity. Think what we could learn by studying it. A whole new realm of understanding…and think what an advantage such an understanding would prove to the first race to acquire it.”
     “And what profits could be made from it,” I said dryly. “Right? And the second reason?”
     “The Silver Ghosts think it’s important. And what they’re interested in, I’m interested in.”
     That made me cough on my wine. “How do you know what the Ghosts are up to?”
     His grin was suddenly boyish. “I’ve got my contacts. And they tell me the Ghosts are sending a ship.”
     I choked again. “Across fifteen billion lights? I don’t believe it.”
     “It’s a fast ship.”

(ed note: Wyman manages to talk Dr. Luce into making the trip to the Lithium-7 event. The ship is only slightly larger than a telephone booth. As it arrives, Dr. Luce realizes that Wyman tricked him. This is a one-way trip, Dr. Luce will run out of air but the ship will transmit all the data back to Wyman.)

     We popped out of Susy-space, sparkling with selectrons and neutralinos.
     My time in that metal box had seemed a lot longer than ten days. I don’t remember a lot of it. I’d been locked inside my head, looking for a place to hide from the oppression of distance, from the burden of looming death. Now I breathed deeply; even the canned air of the pod seemed sweet out of Susy-space. I checked my status. I’d have four days’ life support at the lithium-7 site. It would expire—with me—just when the Ghosts arrived. Wyman had given me the bare bones.
     I de-opaqued my window and looked out. I was spinning lazily in an ordinary sky. There was a powdering of stars, a pale band that marked a galactic plane, smudges that were distant galaxies. Earth was impossibly far away, somewhere over the horizon of the Universe. I shivered. Damn it, this place felt old.

     There was something odd about one patch of sky. It looked the size of a dinner plate at arm’s length. There were no stars in the patch. And it was growing slowly. I set up the monitors. “sWyman (the on-board computer)—what is it?”
     “All I see is a dull infra-red glow…But that’s where the lithium object is hiding, so that’s the way we’re headed.”
     The patch grew until it hid half the sky. I started to make out a speckled effect. The speckles spread apart; it was as if we were falling into a swarm of bees. Soon we reached the outskirts of the swarm. A hail of huge objects shot past us and began to hide the stars behind us— “They’re ships.”
     I straightened up from my monitor. “Ships. Millions of ships, sWyman.”
     I swung the focus around the sky. I picked out a little family of cylinders, tumbling over each other like baby mice. There was a crumpled sphere not much bigger than the pod; it orbited a treelike structure of branches and sparkling leaves. Beyond that I made out bundles of spheroids and tetrahedra, pencils of rods and wands—my gaze roved over a speckling of shape and color. I was at the heart of a hailstorm of ships. They filled the sky, misting into the distance (why, it's a Sargasso of Space!).
     But there was no life, no purposeful movement. It was a desolate place; I felt utterly alone. I looked again at the tree-thing. The delicate ship was miles wide. But there were scorch marks on the leaves, and holes in the foliage bigger than cities. "sWyman, these are wrecks. All of them.”
     A motion at the edge of my vision. I tried to track it. A black, birdlike shape that seemed familiar—
     “Luce, why the junk yard? What’s happened here?”

     I thought of a shell of lithium-stained light growing out of this place and blossoming around the curve of the Universe. At its touch flocks of ships would rise like birds from the stars…“sWyman, we’re maybe the first to travel here from our Galaxy. But races from further in, closer to this event, have been flooding here from the start. As soon as the lithium-7 light reached them they would come here, to this unique place, hoping as we hope to find new understanding. They’ve been seeking the lithium treasure for billions of years…and dying here. Let’s hope there’s still something worth dying for.”

     Something was growing out of the speckled mist ahead. It was a flattened sphere of blood-colored haze; starlight twinkled through its substance. It was impossible to guess its scale. And it kept growing. “sWyman. I think that’s another ship. It may not be solid…but I know we’re going to hit. Where’s my intrasystem drive?”
     “Fifteen billion light years away.” (it was jettisoned near the start of the journey to save mass)
     There was detail in the crimson fog, sparks that chattered around rectangular paths. Now the huge ship shut off half the sky. “Lethe.” I opaqued the window. There was a soft resistance, like a fall into a liquid. Red light played through the pod walls as if they were paper. Sparks jerked through right angles in the air. Then it was over. I tried to steady my breath.
     “Why worry, Michael?” sWyman said gently. “We’ve no power; we’re ballistic. If another of those babies runs into us there’s not a damn thing we can do about it.”

     “It’s getting clearer up ahead.”
     We dropped out of the mist of ships and shot into a hollow space the size of the Solar System. On the far side was another wall of processed matter—more ships, I found. There was a sphere of smashed-up craft clustering around this place like gaudy moths. And the flame at the heart of it all? Nothing much. Only a star. But very, very old…
     Once it had been a hundred times the mass of our sun. It had squirted lithium-7 light over the roof of the young cosmos. It had a terrific time. But the good days passed quickly. What we saw before us was a dried-up corpse, showing only by its gravity signature.

     Just an old star…with something in orbit around it.
     I focused my instruments. “That thing’s about a foot across,” I recorded. “But it masses more than Jupiter…” The monstrous thing crawled past the surface of its wizened mother, raising a blood-red tide.
     “So what? A black hole?”
     I shook my head. “The densities are wrong. This is a different ball game, sWyman. That stuff’s quagma.” The largest piece of quagma I’d had to work with before had been smaller than a proton. This was my field, brought within miraculous reach. I stammered observations—
     Things started to happen.
     The quagma thing veered out of orbit and shot towards us. I watched in disbelief. “It’s not supposed to do that.” I felt a tingle as it hurtled past, mere yards from my window. It looked like a lump of cooling charcoal. Its gravity field slapped the pod as if it were a spinning top, and centripetal force threw me against the wall. Clinging to the window frame I caught a glimpse of the quagma object whirling away from the pod and neatly returning to its orbit.

     Then a shadow fell across the window.
     “That’s shot us full of all sorts of funny stuff,” shouted sWyman. “Particles you wouldn’t believe, radiation at all wavelengths—”
     I didn’t reply. There was a shape hovering out there, a night-dark bird with wings hundreds of miles across. “Xeelee,” I breathed. “That’s what I saw in the ship swarm. The Xeelee are here. That’s a night-fighter—” sWyman roared in frustration.
     The Xeelee let us have it. I saw the exterior of the window glow cherry-red; gobbets melted and flew away. The Xeelee dipped his wings, once; and he flew away. Then the window opaqued. Something hit my head in the whirling darkness. The noise, the burning smells, sWyman’s yelled complaints—it all faded away.
     “…Damn those Xeelee. I should have known they can beat anything we’ve got. And of course they would police this lithium beacon. It wouldn’t do to let us lesser types get our hands on stuff like this; oh no…”
     I was drifting in a steamy darkness. There was a smell of smoke. I coughed, searched for a coffee globe. “At least the Xeelee attack stopped that damn rotation.” sWyman shut up, as if cut off.

     “What’s our status, sWyman?”
     “Nothing that counts is working. Oh, there’s enough to let us interpret the quagma encounter…But, Luce, the inseparability packet link is smashed. We can’t talk to home.” Cradling the cooling globe I probed at my feelings. There was despair, certainly; but over it all I felt an unbearable shame.
     I’d let my life be stolen. And, in the end, it was for nothing. sWyman hissed quietly. “How’s the life support, by the way?” I asked.
     “What life support?”
     I let the globe join the cabin’s floating debris and felt my way to the opaqued window. It felt brittle, half-melted. It would stay opaqued forever, I realized.

     “sWyman. Tell me what happened. When that quagma droplet lunged out of its orbit and sprayed us.”
     “Yeah. Well, the particles from the quagma burst left tracks like vapor trails in the matter they passed through.” I remembered how that invisible shower had prickled. The scars laced everything—the hull, the equipment, even your body. And the tracks weren’t random. There was a pattern to them. There was enough left working in here for me to decipher some of the message…”
     I felt my skin crawl. “A message. You’re telling me there was information content in the scar patterns?”
     “Yes,” said sWyman casually. I guess he’d had time to get used to the idea. “But what we can’t do is tell anyone about it.”
     I held my breath. “Do you want to tell me?”

     It was less than a second after the Big Bang.
     Already there was life. They swarmed through a quagma broth, fighting and loving and dying. The oldest of them told legends of the singularity. The young scoffed, but listened in secret awe.
     But the quagma was cooling. Their life-sustaining fluid was congealing into cold hadrons. Soon, the very superforce which bound their bodies would disintegrate.
     They were thinking beings. Their scientists told them the end of the world, seconds away, would be followed by an eternal cold. There was nothing they could do about it.
     They could not bear to be forgotten.
     So they built…an ark. A melon-sized pod of quagma containing all their understanding. And they set up that unmistakable lithium-7 flare, a sign that someone had been here, at the dawn of time.
     For trillions of seconds the ark waited. At last cold creatures came to see. And the ark began to tell its story.

     I floated there, thinking about it. The scars lacing the pod—even my body—held as much of the understanding of the quagma creatures as they could give us. If I could have returned home engineers could have dissected the pod, doctors could have studied the tracery of tracks in my flesh; and the patterns they found could have been unscrambled.
     Perhaps we would never decipher it all. Perhaps much of it would be meaningless to us. I didn’t know. It didn’t matter. For the existence of the ark was itself the quagma datum, the single key fact:
     That they had been here.
     And so the ark serves its purpose.

From THE QUAGMA DATUM by Stephen Baxter (1989)

      Captain Future fought to break clear of this strong, invisible current, but the rocket-tubes seemed utterly powerless. At appalling speed, the space-boat was whirled through the void.
     He realized the terrible peril into which they had fled. Its nearness had been haunting him during all this time.
     "The cruiser has given up the pursuit!" Joan cried joyfully. "They're turning back – leaving us!"
     Captain Future's tanned face was grim. "They're doing so because they don't want to be trapped as we're trapped."
     "Trapped?" cried Kansu Kane. "What do you mean?"
     "We can't get out of this ether-current," Curt gritted. "It's too strong. And its whirling us on into the most dangerous spot in space, one from which no interplanetary ship has ever escaped."
     Joan's hand went to her throat. "You mean –" Captain Future nodded grimly.
     "Yes. We're being carried into the Sargasso Sea of Space."
     The Sargasso Sea of Space! The legendary, mysterious peril to navigation that was dreaded by every spacesailor in the System!
     Joan Randall's pretty face was pale and stricken, and little Kansu Kane stared bewilderedly, as Captain Future told them that their space-boat was being drawn into that deadly trap.
     The space-boat was still being carried at frightful speed through the void by the ether-current gripping it. The Legion of Doom cruiser, recoiling from the danger, had vanished.
     "It's my fault," Curt Newton said, his tanned face self-accusing. "I knew from the currents that we were getting near the Sargasso. But I thought I could escape it and shake off pursuit."
     "You were wonderful to get us out of that ship!" Joan cried loyally to the red-haired scientific wizard. "And you'll get us out of the Sargasso – I know you will."
     "What is this Sargasso of Space you're talking about?" Kansu Kane demanded. "I'm no space-sailor – I never heard of it."
     "You know what an ether-current is, don't you?" Captain Future asked him. "Well, there are many strong ether-currents, strange running tides in the luminiferous ether itself, out in this part of the System. They all flow into a central vortex, and anything that is carried into the vortex can't get out again, against the currents. That central vortex is the Sargasso Sea of Space."
     Curt reached for the throttles. "I'll try once more to break out of the current," he muttered. "But I'm afraid –"
     He opened the throttles to the limits. It was futile. The power was not enough to get them out of the remorseless grip of the ether-current that was sweeping them fatally on into a dreaded, unknown region of space.
     Captain Future shut off the rockets. "No go," be said, shaking his red head. "Might as well save our power, until we get into the central vortex. Then we'll see what we'll see."
     Clinging for support, they felt their craft batted about by titanic, unseen tides. Everything was topsy- turvy.
     Then, after terrifying minutes of chaotic movement, the space-boat seemed to enter smooth. undisturbed space. It floated now as placidly as though on a millpond.
     "Why, we're out of the currents now." Kansu Kane faltered, peering out with myopic eyes.
     "We've escaped from the Sargasso?" Joan cried joyfully to Captain Future.
     Curt shook his bead. "I'm sorry to disillusion you. We've reached the dead-center of the whirlpool of currents, an area of undisturbed space at the heart of this space-maelstrom."
     He opened the throttles, starting up the rockets. "We'll try to buck our way back out, but I'm pretty sure it's useless."
     Rockets flaming, the little boat shot back in the direction from which it had come. In a half-minute it plunged again into the titanic, invisible ether-currents. The currents grasped the craft once more and flung it like a toy back into the dead-center.
     "Thought so," Curt muttered. "We're in here to stay, unless we can devise enough new power to carry us out."
     "Where do you expect to find any additional source of power in this empty hole in space?" Kansu asked hopelessly.
     "There," said Captain Future quietly, pointing ahead.
     They stared. Far ahead, avast jumbled metal mass floated motionless in space. The mass was lenticular in shape, and hung at the very center of the dead-area here in the maelstrom.
     As their craft hummed closer, they saw that this farflung, jumbled mass was a great aggregation of space ships and debris of all descriptions. All this flotsam was held together by its own slight mutual gravitation.
     "What is it?" Joan Randall whispered awedly.
     "It is the graveyard of space ships," Curt said. "The last resting-place of every ship that has been sucked into the Sargasso Sea of Space since interplanetary travel began. No ship has ever escaped here – all that blundered in are still here."
     In the pack were space ships of every kind that had ever sailed the System. Great Jovian grain-boats, dumpy Martian freighters, streamlined liners from the Neptune and Uranus routes, black cruisers of the Planet Police, ominously armed pirate ships, even small spaceyachts. These dead ships floated, rubbing slowly against each other's sides. And between and among them floated all kinds of interplanetary debris that had been swept into the maelstrom – meteors large and small, fragments of splintered asteroids, bits of metal wreckage, and stiff, space-suited bodies of dead men who perhaps had floated in the void for years before drifting into this last resting place.
     Unutterably awe-inspiring was the sight, here in the thin, pale sunlight of outer space. Here was the end of many a brave-hearted voyage. Here many a good ship that had once throbbed from world to world had come to peace and quiet at last. Here was a Valhalla of space ships and space-men. whose eternal tranquility and silence would not be disturbed until the System ended.
     "Do you think there are any living people in those ships, Captain Future?" asked Joan Randall in a low voice.
     "I'm afraid there's no chance of that. The air-supply of any ship that drifted in here would soon be exhausted, and then any living people aboard would die."
     "Then we will perish when our boat's air-tanks are empty?' the girl cried. "Only two days from now?"
     "We're going to try to get out of here before then"' Curt said grimly. "There's just a chance that if we fitted up this space-boat with additional cyclotrons taken from some of these wrecks, it would give us enough power to fight out through the currents. We'll have to go through the wrecks first and see if we can find enough cyclotrons in good condition," he added.

     Curt stared. She was pointing at a strange object several ships away. It was a cylinder of blank gray metal several hundred feet long, without the lines of a ship at all.
     "I don't know – it's certainly no space ship of our System," Curt declared. "It may be from outside the System – a queer wreck out of interstellar space that drifted into the System and was caught here in the Sargasso." His gray eyes kindled with scientific interest. "We'll take a look. Come on, Joan."
     They started toward the enigmatic cylinder. But they stopped again, before they reached it. stricken with wonder by the appearance of the craft that floated next to it.
     This was a space ship of ridiculously small size and flimsy appearance. It was crudely designed, with projecting rocket-tubes of an ancient, inefficient type. The little vessel was the most antiquated and obsolete of any they had seen yet.
     "Why, it looks like one of the first space ships that was ever built!" Joan cried. "Could men ever have sailed space in a craft like that?"
     Curt's tanned face was suddenly tense and strange. "I've an idea I know what craft this is," he said. "Yes, I'm right-look at the name on its bows!" The name was Pioneer III.
     "Pioneer III?" cried Joan. "Why, that was the ship of Mark Carew, the first man ever to –"
     "The first man ever to sail beyond Jupiter," Captain Future finished softly, staring almost in reverence at the clumsy little craft. "Mark Carew, the second great trailblazer of space – the man who first visited Saturn and Uranus and Neptune, and who was lost in space in a later voyage. And this is where he was lost, here in the Sargasso."

(ed note: in other words a historical ship dating to the dawn of space flight)

     Next moment, he stiffened inside his space suit and heard a sharp cry from Joan. A door was opening in the cylinder.
     It opened like the iris shutter of a camera, expanding from a tiny aperture into a circular opening ten feet across.
     "What opened that door?" cried the girl, panic-stricken. "We weren't even near it."
     Curt's gray eyes flashed. "That door must be telepathically operated—when I wished a door would open, it opened!"

From CALLING CAPTAIN FUTURE by Edmond Hamilton (1940)

      Five years. Five years ago Barbara Jean Ramsey and their son Harold were due back from Meiji. Superstitiously, Bart had waited for them before accepting his promotion... Barbara Jean had never come home from Meiji. Her ship had taken a new direct route along an Alderson path just discovered. It never came out into normal space. A scoutcraft was sent to search for the liner, and Senator Grant (Barbara's father) had enough influence to send a frigate after that. Both vanished, and there weren’t any more ships to send.

     “You got five forces in this universe we know about, ja? Only one of them maybe really isn’t in this universe; we do not quibble about that, let the cosmologists worry. Now we look at two of those forces, we can forget the atomics and electromagnetics. Gravity and the Alderson force, these we look at. Now you think about the universe as flat like this table, eh?” He swept a pudgy hand across the roseteak surface. “And wherever you got a star, you got a hill that rises slowly, gets all the time steeper until you get near the star when it’s so steep you got a cliff. And you think of your ships like roller coasters. You get up on the hill, aim where you want to go, and pop on the hyperspace drivers. Bang, you are in a universe where the Alderson effect acts like gravity. You are rolling downhill, across the table, and up the side of the next hill, not using up much potential energy, so you are ready to go again somewhere else if you can get lined up right, O.K.?”
     Ramsey frowned. “It’s not quite what we learned as middies—you’ve got ships repelled from a star rather than—”
     “Ja, ja, plenty of quibble we can make if we want to. Now, Captain, how is it you get out of hyperspace when you want to?”
     “We don’t,” Ramsey said. “When we get close enough to a gravity source, the ship comes out into normal space whether we want it to or not.”
     Stirner nodded. “Ja. And you use your photon drivers to tun around in normal space where the stars are like wells, not hills, at least thinking about gravities. Now, suppose you try to shoot past one star to another, all in one jump?”
     “It doesn’t work,” Ramsey said. “You’d get caught in the gravity field of the in-between star. Besides, the Alderson paths don’t cross each other. They’re generated by stellar nuclear activities, and you can only travel along lines of equal flux. In practice that means almost line of sight with range limits, but they aren’t really straight lines. . . .”
     “Ja. O.K. That’s what I think is happening to them. I think there is a star between A-7820 and 82 Eridani, which is the improbable name Meiji’s sun is stuck with.”
     “Now wait a minute,” Admiral Torrin protested. “There can’t be a star there, Professor. There’s no question of missing it, not with our observations. Man, do you think the Navy didn’t look for it? A liner and an explorer class frigate vanished on that route. We looked, first thing we thought of.”
     “Suppose there is a star there but you are not seeing it?”
     “How could that be?” Torrin asked.
     “A Black Hole, Admiral. Ja,” Stirner continued triumphantly. “I think Senator Grant fell into a Black Hole.”

     “Then how would Black Holes interact with—oh,” Rap Torrin said, “gravity. It still has that.”
     Stirner’s round face bobbed in agreement. “Ja, ja, which is how we know is no black galaxy out there. Would be too much gravity. But there is plenty of room for a star. Now one thing I do not understand though, why the survey ship gets through, others do not. Maybe gravity changes for one of those things, ja?”
     “No, look, the Alderson path really isn’t a line of sight, it can shift slightly—maybe just enough!” Torrin spoke rapidly. “If the geometry were just right, then sometimes the Hole wouldn’t be in the way. . . .”
     “O.K.,” Stirner said. “I leave that up to you Navy boys. But you see what happens, the ship is taking sights or whatever you do when you are making a jump, the captain pushes the button, and maybe you come out in normal space near this Black Hole. Nothing to see anywhere around you. And no way to gets back home.”
     “Of course.” Ramsey stood, twisted his fingers excitedly. “The Alderson effect is generated by nuclear reactions. And the dark holes—”
     “Either got none of those, or the Alderson force stuff is caught inside the Black Hole like light and everything else. So you are coming home in normal space or you don’t come home at all.”

(ed note: in other words the ships fell into the interstellar Bermuda Triangle and are currently caught in the Sargasso Sea of Space)

     “Which is light-years. You’d never make it.” Ramsey found himself near the bar. Absently he poured a drink. “But in that case—the ships can sustain themselves a long time on their fuel!”
     “Yes.” Lermontov said it carefully. “It is at least possible that Senator Grant is alive. If his frigate dropped into normal space at a sufficient distance from the Black Hole so that it did not vanish down.”
     “Not only Martin,” Bart Ramsey said wonderingly. His heart pounded. “Barbara Jean. And Harold. They were on a Norden Lines luxury cruiser, only half the passenger berths taken. There should have been enough supplies and hydrogen to keep them going five years, Sergei. More than enough!”

(ed note: Spoiler: a rescue mission is sent. The only way to get back is to somehow generate a large nuclear reaction to create the Alderson effect. Crashing one of the trapped starships on the Black Hole will work. Unfortunately this is even more difficult that crashing a ship onto the Sun: the intense gravity will make the ship miss if you are a fraction of a degree off. Which means some brave volunteer will have to sacrifice themself to save the others, manually piloting the ship into a collision while the rescue ship is poised to jump. The rescue ship waits with their Alderson drive turned on, when the crashing ship creates the Alderson effect the drive will have something to make the ship jump.)

From HE FELL INTO A DARK HOLE by Jerry Pournelle (1973)

Welded Ball of Dead Ships

There are several examples of people discovering a Sagasso of Space, then welding all the ships together to make a ramshackle space habitat. I didn't think there would be more than one, but here we are.

Sometimes the ball was created by marooned crew trapped in a Sagasso of Space, and there is some reason or other that survival requires the ships to be attached to each other.

Sometimes the ball is created at a site with something that attracts people, like an asteroid mining strike. A boomtown in other words. If the attractive item vanishes (e.g., the asteroid strike becomes all mined out), then the boom goes bust and the boomtown ship ball becomes a ghost town ship ball.

And sometimes the ball is created by people running away from something repulsive, like a pogrom or a war. In other words: a refugee camp, hobo jungle, or shanty town.

Most welded balls of ships are non-mobile, interesting exceptions include Romany and the COVID-19 Coco Bay cruise liners.

Some welded balls are well-known and quite visible. Some are obscure and located in distant backwaters of the galaxy. Many that are located in a sargasso are invisible and hidden inside a pocket universe with a hard-to-find portal.


(ed note: Waystar is the legendary pirate haven. Zilwrich is a Zacathan alien, noted archaeologists and historians. They have a life span of about a thousand years. The "Guild" is the Thieves Guild)

"You are right that it was a raid for the treasures we found within a tomb. It is a very rich find and a remainder of a civilization not heretofore charted. So it is worth far more than just the value of the pieces—it is worth knowledge!" And he provided that last word with such emphasis as I might accord a flawless gem. "They will sell the treasure to those collectors who value things enough to hide them for just their own delight. And the knowledge will be lost!"

"You know where they take it?" Eet asked.

"To Waystar. So it would seem that that is not a legend after all.

"They blasted into hyper. We cannot track them." Ryzk shook his head. "And the site of Waystar is the best-guarded secret in the galaxy."

But I held a session in which we pooled what we knew of Waystar. Since most was only legend and space tales, it would be of little value, a statement I made gloomily.

But Zilwrich differed. "We Zacathans are sifters of legends, and we have discovered many times that there are rich kernels of truth hidden at their cores. The tale of Waystar has existed for generations of your time, Murdoc Jern, and for two generations of ours—"

"That—that means it antedates our coming into space!" Ryzk interrupted. "But—"

"Why not?" asked the Zacathan. "There have always been those outside the law. Do you think your species alone invented raiding, crime, piracy? Do not congratulate or shame yourselves that this is so. Star empires in plenty have risen and fallen and always they had those who set their own wills and desires, lusts and envies, against the common good. It is perfectly possible that Waystar has long been a hide-out for such, and was rediscovered by some of your kind fleeing the law, who thereafter put it to the same use. Do you know those co-ordinates?" he asked Ryzk.

The pilot shook his head. "They are off any trade lane. In a 'dead' sector."

"And what better place—in a sector where only dead worlds spin about burned-out suns? A place which is avoided, since there is no life to attract it, no trade, no worlds on which living things can move without cumbersome protection which makes life a burden."

"One of those worlds could be Waystar?" I hazarded.

"No. The legend is too plain. Waystar is space-borne. Perhaps it was even once a space station, set up eons ago when the dead worlds lived and bore men who reached for the stars. If so, it has been in existence longer than our records, for those worlds have always been dead to us."

He had given us a conception of time so vast we could not measure it. Ryzk frowned.

"No station could go on functioning, even on atomics—"

"Do not be too sure even of that," Zilwrich told him. "Some of the Forerunners had machines beyond our comprehension. You have certainly heard of the Caverns of Arzor and of that Sargasso planet of Limbo where a device intended for war and left running continued to pull ships to crash on its surface for thousands of years. It is not beyond all reckoning that a space station devised by such aliens would continue to function. But also it could have been converted, by desperate men. And those criminals would thus have a possession of great value, if they could continue to hold it—something worth selling—"

"Safety!" I cut in. Though Waystar was not entirely Guild, yet surely the Guild had some ties there.

"Just so," agreed Eet. "Safety. And if they believe they have utter safety there we may be sure of two things. One, that they do have some defenses which would hold perhaps even against Fleet action, for they cannot think that the situation of their hole would never be discovered. Second, that having been so long in the state of safety, they might relax strict vigilance."

However, on the visa-screen what we picked up now was not the ship, but what lay ahead. For additional safety Eet had snapped on the distort beam and through that we could see just a little of the amazing port we neared.

Whatever formed its original core—an asteroid, a moon, an ancient space station—could not be distinguished now. What remained was a mass of ships, derelicts declared so by their broken sides, their general decrepit appearances. They were massed, jammed tightly together into an irregular ovoid except in one place directly before us, where there was a dark gap, into which the ship controlling our path was now headed.

"Looted ships—" I hazarded, ready to believe now in every wild story of Waystar. Pirates had dragged in victim ships to help form their hiding place—though why any such labor was necessary I could not guess.

The band of murdered ships ended suddenly in a clear space, a space which held other ships—three I could see. One was the cargo ship which had brought us in, another was one of those needle-nosed, deadly raiders I had seen used by the Guild, and the third was plainly a yacht. They were in orbit around what was the core of this whole amazing world in space. And it was a station, oval in shape like the protecting mass of wreckage, with landing stages at either end. Its covering was opaque, but with a crystalline look to the outer surface, which was pitted and pocked and had obviously been mended time and time again with substances that did not match the original material.

From UNCHARTED STARS by Andre Norton (1969)

(ed note: In the swamps of Venus, the aboriginal tribe called the Kraylens have the misfortune to be living atop rich deposits of coal, oil, and valuable minerals. The Coalition Government wants to annex the ancestral tribal lands, put all the Kraylens in scattered reservations to die, and strip mine the resources. Earthman interplanetary rogue Roy Campbell had been nursed back to health by the Kraylens, and owes them a debt. He seeks to settle the Kraylens on the Romany: an space colony assembled out of derelict spaceships. The Romany is a refuge for the displaced. In the past they had helped the Shenyat people on Ganymede and the Drylanders on Mars.

Note that the term "Gypsy" is considered offensive by some)

      Now the Kraylens were going the way of the others, straws swept before the great broom of Progress. Nothing could stop it. Earth's empire surged out across the planets, building, bartering, crashing across time and custom and race to make money and the shining steel cage of efficiency.
     A cage wherein a sheep could live happily enough, well-fed and opulent. But Campbell wasn't a sheep. He'd tried it, and he couldn't bleat in tune. So he was a wolf, now, alone and worrying the flock.
     Soon there wasn't going to be a place in the Solar System where a man could stand on his own feet and breathe.

     It was full day when he reached his hidden ship—a sleek, souped-up Fitts-Sothern that had the legs of almost anything in space. He paused briefly by the airlock, looking at the sultry green of liha-trees under a pearl-gray sky, the white mist lapping around his narrow waist.
     He spent a long time over his charts, feeding numbers to the computers. When he got a set-up that suited him, he took the Fitts-Sothern up on purring 'copters, angling out over the deep swamps. He felt better with the ship under his hands.
     The Patrol blanket was thin over the deep swamps, but it was vigilant. Campbell's nerves were tight. They got tighter as he came closer to the place where he was going to have to begin his loop over to the night side.
     He was just reaching for the drive switch when the little red light started to flash on the indicator panel.
     Somebody had a detector beam on him. And he was morally certain that the somebody was flying a Patrol boat.

     THERE was one thing about the Venusian atmosphere. You couldn't see through it, even with infra-beams, at very long range. The intensity needle showed the Patrol ship still far off, probably not suspicious yet, although stray craft were rare over the swamps.
     In a minute the copper would be calling for information, with his mass-detectors giving the stray a massage. Campbell didn't think he'd wait. He slammed in the drive rockets, holding them down till the tubes warmed. Even held down, they had plenty.
     The Fitts-Sothern climbed in a whipping spiral. The red light wavered, died, glowed again. The cop was good with his beam. Campbell fed in more juice.
     The red light died again. But the Patrol boat had all its beams out now, spread like a fishnet. The Fitts-Sothern struck another, lost it, struck again, and this time didn't break out.

     Campbell felt the sudden racking jar all through him. "Tractor beams," he said. "You think so, friend?"
     The drive jets were really warming now. He shot it to them. The Fitts-Sothern hung for a fractional instant, her triple-braced hull shuddering so that Campbell's teeth rang together.
     Then she broke, blasting up right through the netted beams. Campbell jockeyed his port and starboard steering jets. The ship leaped and skittered wildly. The cop didn't have time to focus full power on him anywhere, and low power to the Fitts-Sothern was a nuisance and nothing more.
     Campbell went up over the Patrol ship, veered off in the opposite direction from the one he intended to follow, hung in a tight spiral until he was sure he was clean, and then dived again.
     The Patrol boat wasn't expecting him to come back. The pilot was concentrating on where Campbell had gone, not where he had been. Campbell grinned, opened full throttle, and went skittering over the curve of the planet to meet the night shadow rushing toward him.
     He didn't meet any more ships. He was way off the trade lanes, and moving so fast that only blind luck could tag him. He hoped the Patrol was hunting for him in force, back where they'd lost him. He hoped they'd hunt a long time.

     Presently he climbed on slowed and muffled jets, out of the atmosphere. His black ship melted indistinguishably into the black shadow of the planet. He slowed still more, just balancing the Venus-drag, and crawled out toward a spot marked on his chart.
     An Outer Patrol boat went by, too far off to bother about. Campbell lit a cigarette with nervous hands. It was only a quarter smoked
     His infra-beam showed it clearly. A round, plate-shaped mass about a mile in diameter, built of three tiers of spaceships. Hulks, ancient, rusty, pitted things that had died and not been decently buried, welded together in a solid mass by lengths of pipe let into their carcasses.
     Before, when he had seen it, Campbell had been in too much of a hurry to do more than curse it for getting in his way. Now he thought it was the most desolate, Godforsaken mass of junk that had ever made him wonder why people bothered to live at all.

     He touched the throttle, tempted to go back to the swamps. Then he thought of what was going to happen back there, and took his hand away.
     "Hell!" he said. "I might as well look inside."
     He didn't know anything about the internal set-up of Romany—what made it tick, and how. He knew Romany didn't love the Coalition, but whether they would run to harboring criminals was another thing.
     It wouldn't be strange if they had been given pictures of Roy Campbell and told to watch for him. Thinking of the size of the reward for him, Campbell wished he were not quite so famous.
     Romany reminded him of an old-fashioned circular mousetrap. Once inside, it wouldn't be easy to get out.

     "Of all the platinum-plated saps!" he snarled suddenly.
     "Why am I sticking my neck out for a bunch of semi-human swamp-crawlers, anyhow?"
     He didn't answer that. The leading edge of Romany knifed toward him. There were lights in some of the hulks, mostly in the top layer. Campbell reached for the radio.
     He had to contact the big shots. No one else could give him what he needed.
     To do that, he had to walk right up to the front door and announce himself. After that. . . .
     The manual listed the wavelength he wanted. He juggled the dials and verniers, wishing his hands wouldn't sweat.
     "Spaceship Black Star calling Romany. Calling Romany."
     His screen flashed, flickered, and cleared. "Romany acknowledging. Who are you and what do you want?"

(ed note: Campbell gets in touch with Tredrick, the chief councilor of Romany. Who tells Campbell to get lost, Romany cannot help the Kraylens. Campbell does not know it yet but Tredrick is a traitor to Romany, planning to betray them all to the Coalition.

Tredick signs off. But before Campbell can leave, another person radios. Somebody named Taxil. He tells Campbell that some still consider the Romany a refuge, Tredrick does not speak for everybody. He instructs Campbell to go to one of the Romany's emergency hatchways hidden on the lowest tier. Campbell does so.)

     Campbell cleared ship. His nerves were singing in little tight jerks. He'd stepped into something here. Something big and ugly. There had been a certain ring in the Taxil's voice.
     The thin, gravelly Mr. Tredrick had something on his mind, too. Something important, about Kraylens. Why Kraylens, of all the unimportant people on Venus?
     Trouble on Romany. Romany the gypsy world, the Solar System's stepchild. Strictly a family affair. What business did a public enemy with a low number and a high valuation have mixing into that? Roy Campbell called himself a short, bitter name, and sighed, and reached lean brown hands for the controls.

     Presently, in the infrafield, he made out an ancient Krub freighter on the edge of the lowest level, connected to companion wrecks by sections of twelve-foot pipe. There was a hatch in one of the pipes, with a handwheel.The Fitts-Sothern glided with exquisite daintiness to the pipe, touched it gently, threw out her magnetic grapples and suction flanges, and hung there. The airlock exactly covered the hatchway.
     Campbell got up. He was sweating and as edgy as a tomcat on the prowl. With great care he buckled his heavy gun around his narrow hips. Then he went into the airlock. He checked grapples and flanges with inordinate thoroughness. The hatch wheel jutted inside. He picked up a spanner and turned it, not touching the frigid metal. There was a crude barrel-lock beyond. Campbell ran his tongue once over dry lips, shrugged, and climbed in.
     He got through into a space that was black as the Coalsack. The air was thin and bitingly cold. Campbell shivered in his silk shirt. He laid his hand on his gun butt and took two cautious steps away from the bulge of the lock, wishing to hell he were someplace else.

(ed note: Campbell is captured by a desperate group who are convinced that he is a spy sent by Tredrick. Before they kill him the Taxil calls to vouch for Campbell.)

     He shrugged. "All right. I'm Roy Campbell."
     "That," said Marah softly, "helps a lot!" He could have meant it any way. His hook made a small, savage flash in the green light. "There's trouble here on Romany. Civil war. Men are going to be killed before it's over—perhaps now. Where's your place in it?"
     "How do I know? The Coalition is moving in on the Kraylens. I owe them something. So I came here for help. Help! Yeah."
     "You'll get it," said the woman. "You'll get it, somehow, if any of us live."
     Campbell raised his dark brows. "What goes on here, anyhow?"

     The woman's low voice sang and throbbed against the pipe walls. "A long time ago there were a few ships. Old ships, crowded with people who had no homes. Little, drifting people who made a living selling their odd handicrafts in the spaceports, who were cursed as a menace to navigation and distrusted as thieves. Perhaps they were thieves. They were also cold, and hungry, and resentful.
     "After a while the ships began to band together. It was easier that way—they could share food and fuel, and talk, and exchange ideas. Space wasn't so lonely. More and more ships drifted in. Pretty soon there were a lot of them. A new world, almost.
     "They called it Romany, after the wandering people of Earth, because they were g*psies, too, in their own way.
     "They clung to their own ways of life. They traded with the noisy, trampling people on the planets they had been driven away from because they had to. But they hated them and were hated, just as g*psies always are.
     "It wasn't an easy life, but they were free in it. They could stand anything, as long as they were free. And always, anywhere in the Solar System, wherever some little lost tribe was being swallowed up and needed help, ships from Romany went to help them."
     Her voice dropped. Campbell thought again of the Kraylen's drum, singing the anger in the indigo night.
     "That was the creed of Romany," she whispered. "Always to help, always to be a refuge for the little people who couldn't adjust themselves to progress, who only wanted to die in dignity and peace. And now…"
     "And now," said Marah somberly, "there is civil war."

     Campbell drew a long, unsteady breath. The woman's voice throbbed in him, and his throat was tight. He said, "Tredrick?"
     Marah nodded. "Tredrick. But it's more than that. If it were only Tredrick, it wouldn't be so bad."
     He ran the curve of his hook over his scarred chin, and his eyes burned like candle flames.
     "Romany is growing old, and soft. That's the real trouble. Decay. Otherwise, Tredrick would have been kicked into space long ago. There are old men in the Council, Campbell. They think more of comfort than they do of—well…"

     "Yeah. I know. What's Tredrick's angle?"
     "I don't know. He's a strange man—you can't get a grip on him. Sometimes I think he's working for the Coalition." (He is. He plans to betray Romany to the Coalition)
     Campbell scowled. "Could be. You g*psies have a lot of wild talents and some unique skills—I've met some of them. The man that controlled them would be sitting pretty. The Coalition would like it, too."
     The woman said bitterly, "And they could always exhibit us. Tours, at so much a head. So quaint—a cross-section of a lost world!"
     "Tredrick's the strong man," Marah went on. "Eran Mak is Chief Councilor, but he does as Tredrick tells him. The idea is that if Romany settles down and stops getting into trouble with the Planetary Coalition, we can have regular orbits, regular trade, and so on."
     "In other words," said Campbell, dryly, "stop being Romany."
     "You understand. A pet freak, a tourist attraction, a fat source of revenue." Again the savage flash of the hook. "A damned circus!"
     "And Tredrick, I take it, has decided that you're endangering the future of Romany by rebellion, and put the finger on you."
     She laughed, and they started off, moving with quick sureness in the black, icy darkness.

     The ship, it seemed, was up on the second level, on the edge of the living quarters. Down here was all the machinery that kept Romany alive—heat, light, water, air, and cooling systems—and a lot of storage hulks.
     The third tier was a vast hydroponic farm, growing the grain and fruit and vegetables that fed the Romany thousands.
     Stumbling through pipes and dismantled hulks that smelled of sacking and dried vegetables and oil, Campbell filled in the gaps.

     The leaders of the rebel element had held a meeting down here, in secret. Marah and the girl had been coming from it when Campbell blundered into them. The decision had been to rescue the Kraylens, no matter what happened.
     They'd known about the Kraylens long before Campbell had. G*psies trading in Lhi had brought word. Now the Kraylens were a symbol over which two points of view were clashing in deadly earnest.

     He became gradually aware of a broken, rhythmic tap and clank transmitted along the metal walls.
     "Hammers," said Stella softly. "Hammers and riveters and welders, fighting rust and age to keep Romany alive. There's no scrap of this world that wasn't discarded as junk and reclaimed by us."
     Her voice dropped. "Including the people."
     Campbell said, "They're scrapping some beautiful things these days."
     She knew what he meant. She even laughed a little. "I was born on Romany. There are a lot of Earth people who have no place at home."

     They went up a wooden ladder. It was suddenly getting hot. Campbell guessed that Romany was in the sun again. The Martian opened a door at the top, very, very slowly.
     A young, vibrant voice sang out, "All clear!" They piled out of the doorway. Four or five husky young Paniki barbarians from Venus stood grinning beside two bound and slumbering Earthmen.

     Campbell stared past them. The air was still and hot, hung with veils of steamy mist. There was mossy earth dotted with warm pools. There were liha-trees, sultry green under a pearly light that was still brightening out of indigo gloom.
     A slow, hot breath of wind stirred the mist and liha-trees. It smelt of warm still water and growing things, and—freedom.
     Campbell drew a long breath. His eyes stung and the veins in his neck hurt. He knew it was a dead hulk, with an iron sky above the pearl-gray mist. But it smelled of freedom.

     They went, through the seven hulks of the Venusian Quarter. Because of the Kraylens, most of the Venusians were with the rebels, but even so there were angry voices raised, and fists, and a few weapons, and some blood got spilled.
     More tow-headed young men joined them, and squat little upland nomads who could talk to animals, and three four-armed serpentine crawlers from the Lohari swamps.
     They came presently to a huge dismantled freighter on the edge of the Venusian Quarter. There were piles of goods waiting lading through the row of airlocks, into smaller trading ships. Marah stopped, his gorget shooting wicked jeweled sparks in the sunlight that seared in through half-shuttered ports, and the others flowed in behind him.
     They were on a narrow gallery about halfway up the inner wall. Campbell looked down. There were people on the ladders and the two balcony levels below. A sullen, ugly mob of people from Earth, from Venus, from Mars and Mercury and the moons of Jupiter and Saturn.

From CITADEL OF LOST SHIPS by Leigh Brackett (1943)

      She’d been four when her family had left Earth (when the Drej Empire destroyed Earth), and had a few memory holos of that first trip into space. One was very clear, a man pointing at a control panel, the shiny plastic of the panel glinting in the dim shiplights, and the faint smell of hot electronics.
     There was something about it that had stuck with her. Something good about controls.
     Controls could take her places.
     She’d begun training as soon as she was old enough, but that wasn’t possible. It hadn’t been easy just surviving.

     Her family had been split up in the mass exodus from Earth, those who made it at all, and her grandmother alone had supported her when they reached the drifter colonies.
     The Earther ships had run as far as they could from the devastating Drej. Other aliens, who had befriended Humanity, who had been so helpful when there were enough resources to be had, grudgingly granted leases to minor moons or asteroids in a variety of systems—at a price, of course.
     The ships that had run were joined into huge orbiting colonies over these rocks. Huge orbiting colonies with little or sometimes no future.
     Naturally, the aliens had given the Humans the very worst of their real estate; what minerals and resources the drifters managed to scrounge went straight into maintaining the colonies. Making a profit had to come from somewhere else. Like most places with few resources, a variety of options had been tested.
     Some of the colonies tried gambling. Others, like Houston, worked to develop a labor pool that could be hired. Nobody was much impressed with Humans, but if they could do the job, and do it cheaper, they’d get hired.

     Cale walked with Akima through the drifter colony marketplace. The colony, called New Bangkok, was a study in contrasts, and the marketplace fit right in. Tables and stalls that wouldn’t have been out of place in a medieval village stood on top of pitted plasteel, right next to emergency life-support stations. The stations looked exactly like the kind found on Tau-14, bubbles to run to in the event of a hull breach.
     Which might be likely on a hulk like New Bangkok; like most drifter colonies, it was made up of hundreds of ships that had come from Earth and been assembled into a form for which they had never been designed.

     Stranger than the look of the colony, however, were the people. Cale couldn’t put his finger on it, but there was an odd air about them. They weren’t particularly strange on themselves—they bustled around just like people on Tau-14. He did notice a sense of poverty to them—he saw few shipsuits that didn’t have patches— but no one looked like they were starving.
     And then, as he watched a group of children gathered around an ice-cream stand, it hit him: This was a community that was made up of Humans. He hadn’t seen more than a handful of nonhumans since they’d entered the station airlock.

     We’re the majority here.

     Maybe that explained the lack of caution and the confidence of everyone he saw. On Tau-14, Humans were second class, always careful not to offend nonhumans lest they pay the price. Here, they didn’t have to.
     For as long as Cale could remember he’d been in the minority. Even during the time he’d spent on Tek’s home world, being Human had meant being an outsider.
     Seeing such a community was very different.

     Ahead of him, Akima was picking over some odd-looking shoes. A nearby sign proclaimed FROM EARTH!
     Cale moved up alongside her. “You going to get some more Earth junk?” he asked.
     Akima tumed to him. “You don’t get it, do you Cale? This junk is all that’s left of where we came from. It isn’t just stuff. Each piece is a reminder of what it means to have a place—to have a home.”

     So he’d waited next to Akima. To his surprise, after only an hour or so, the woman had retumed with a man who’d said he was the mayor of the oldest section of New Bangkok, the original ship collection. The habitat had expanded since then, but some of the original refugee ships, which early colonists had joined with a variety of makeshift conduits and couplings, were still there. The mayor had explained that his ship was so old that it hadn’t meshed well with the more modern majority.
     “Besides,” the old man had said, “I wanted to be ready to run again—if we ever needed to.”

From TITAN A. E. by Dal Perry and Steve Perry (2000)

      BETWEEN MARS AND JUPITER is spread the broad belt of the asteroids. Of the thousands, known and unknown, most unique to the Freak Century was the Sargasso Asteroid, a tiny planet manufactured of natural rock and wreckage, salvaged by its inhabitants in the course of two hundred years.
     They were savages, the only savages of the twenty-fourth century; descendants of a research team of scientists that had been lost and marooned in the asteroid belt two centuries before when their ship had failed. By the time their descendants were rediscovered they had built up a world and a culture of their own, and preferred to remain in space, salvaging and spoiling, and practicing a barbaric travesty of the scientific method they remembered from their forebears. They called themselves The Scientific People. The world promptly forgot them.

     S.S. Nomad looped through space, neither on a course for Jupiter nor the far stars, but drifting across the asteroid belt in the slow spiral of a dying animalcule. It passed within a mile of the Sargasso Asteroid, and it was immediately captured by The Scientific People to be incorporated into their little planet. They found Foyle.

     He awoke once while he was being carried in triumph on a litter through the natural and artificial passages within the scavenger asteroid. They were constructed of meteor metal, stone, and hull plates. Some of the plates still bore names long forgotten in the history of space travel: INDUS QUEEN, TERRA; SYRTUS RAMBLER, MARS; THREE RING CIRCUS, SATURN. The passages led to great halls, storerooms, apartments, and homes, all built of salvaged ships cemented into the asteroid.
     In rapid succession Foyle was borne through an ancient Ganymede scow, a Lassell ice borer, a captain's barge, a Callisto heavy cruiser, a twenty-second-century fuel transport with glass tanks still filled with smoky rocket fuel. Two centuries of salvage were gathered in this hive: armories of weapons, libraries of books, museums of costumes, warehouses of machinery, tools, rations, drink, chemicals, synthetics, and surrogates.

     Foyle fainted.

     He awoke again. He had been taken out of his spacesuit. He was in the greenhouse of the asteroid where plants were grown for fresh oxygen. The hundred-yard hull of an old ore carrier formed the room, and one wall had been entirely fitted with salvaged windows … round ports, square ports, diamond, hexagonal … every shape and age of port had been introduced until the vast wall was a crazy quilt of glass and light.

     Foyle explored. He was in the main cabin of a small rocket launch of the early 2300's … once a private yacht. The main cabin had been converted into a bedroom.
     He lurched to the ports and looked out. The launch was sealed into the mass of the asteroid, connected by passages to the main body. He went aft. Two smaller cabins were filled with growing plants for oxygen. The engine room had been converted into a kitchen. There was Hi-Thrust in the fuel tanks, but it fed the burners of a small stove atop the rocket chambers. Foyle went forward. The control cabin was now a parlor, but the controls were still operative.
     He went aft to the kitchen and dismantled the stove. He reconnected the fuel tanks to the original jet combustion chambers. M♀ira followed him curiously.
     What are you doing, N♂mad?"
     "Got to get out of here, girl." Foyle mumbled. "Got business with a ship called Vorga. You dig me, girl? Going to ram out in this boat, is all."
     Foyle finished his rough patching of the engine room; he was almost an expert by now. He picked up the writhing girl and took her to the main hatch.
     "Leaving," he shouted in M♀ira's ear. "Takeoff. Blast right out of asteroid. Hell of a smash, girl. Maybe all die, you. Everything busted wide open. Guesses for grabs what happens. No more air. No more asteroid. Go tell'm. Warn'm. Go, girl."
     He opened the hatch, shoved M♀ira out, slammed the hatch and dogged it. The charivari stopped abruptly.

     At the controls Foyle pressed ignition. The automatic take-off siren began a howl that had not sounded in decades. The jet chambers ignited with dull concussions. Foyle waited for the temperature to reach firing heat. While he waited he suffered. The launch was cemented into the asteroid. It was surrounded by stone and iron. Its rear jets were flush on the hull of another ship packed into the mass. He didn't know what would happen when his jets began their thrust, but he was driven to gamble by Vorga.
     He fired the jets. There was a hollow explosion as Hi-Thrust flamed out of the stern of the ship. The launch shuddered, yawed, heated. A squeal of metal began. Then the launch grated forward. Metal, stone and glass split asunder and the ship burst out of the asteroid into space.

From THE STARS MY DESTINATION by Alfred Bester (1956)

      According to Nee'Lix, the space station orbiting the black star had had many names over the millennia, but nowadays most people just called it the Array. It was the Outer Rim terminal of a network of portals that spanned the galaxy, the work of an ancient species whose existence would be attributed to myth were it not for this undeniable evidence of their technological prowess: a gargantuan cylinder of super-dense material allegedly mined from the collapsed star itself, impervious to Time or the efforts of lesser species to fathom its nature. Wars involving weapons of terrible destructive force had been fought over the portals without inflicting the slightest damage—except of course on the colonies that invariably clustered on their outer surface like barnacles on the hull of an ancient sailing ship. Thousands of derelict spacecraft—ranging from tiny lifepods to colossal generation ships—had been permanently moored to makeshift docking cradles and converted into trading posts and habitats and manufactories. Their portholes and beacon lights cast a baleful lumination in the absolute dark of the black star, ugly and beautiful as an anglerfish in the sunless ocean depths.

     From where he sat on the prow of the shuttleboat, Tom Paris could see at least a dozen spacecraft lined up inside the cylindrical interior of the Array which—unlike its congested outer surface—was as bare and smooth as a gun barrel aimed at the heart of the black star. Exactly how the portal worked was a mystery. The technos and eggheads had been arguing over the subject since they first arrived, throwing around terms like 'transwarp conduits' and 'graviton catapults', but when Paris had suggested the portal could dematerialize a rocketship and beam it across the galaxy like a radio signal, the Science Department and the Glowing Gang had agreed for the first time ever by deriding teleportation as Fortean nonsense that would require more energy than was available in the entire Universe, and violated Heisenberg's Theory of Uncertainty as well.

     He pressed down the chin-plate to switch his radio to 'send'. "Let me get this straight, Nee'Lix. The Briori give safe passage to spacecraft passing through the portal network, while using that same network to send out their pirates to seize other spacecraft and drag them back here, so they can be stripped down and fixed to the Array like trophies?"

     "You've got it, Mr. Paris." The latest addition to their crew was peering through the viewing slit of a decompression shelter-balloon that had been lashed to the observer's seat. It was the only spacesuit available that could fit his non-anthropoid frame. "Sometimes the passage isn't that safe either. It's not unknown for a K'Zon warship on convoy escort to be attacked by another K'Zon sect out raiding. They say the Briori secretly encourage this to keep the sects at each other's throats, so they won't join forces and seize the portal network for themselves. It's an uneasy alliance all round."

     Three days had passed since Voyager first matched velocities with the Array, and their arrival seemed a matter of little import. No space pirates had bothered them (apparently the Briori preferred to keep trouble far from their own bailiwick) but Captain Janeway had decided to keep the ship well clear so they would have the freedom to maneuver if needed. That meant ferrying everyone over by shuttleboat and Voyager only had three of those, one of which was being cannibalized for spare parts after sustaining damage during the Resettlement. Paris was piloting a Type 6, a bare-bones shuttleboat designed to operate solely in Outer Space. Just two seats and a control board wired to a rocket engine, propellant tanks and a couple of thruster rings, all bolted to a latticework cage to which cargo pods, radiosondes or automatic cannon could be attached to adapt it to any task. Easily modified and repaired, they were the workhorses of Spacefleet.

     Paris muttered. He toggled a row of oversized switches, clasped the pincers of his space armor around the control yoke and eased it forward. There was a noiseless vibration and he was shoved back into his seat as the engine fired. Back home this would all be done automatically, their robot-pilot locked onto a radar beacon, but Federation-standard electronics were not designed for anything out here.

     'This is how flying should be done', thought Paris. 'By the seat of your pants like Father did in the War'.

     As the Array filled his field of vision Paris turned on the landing beacons, the searchlights illuminating the Sargasso Sea of derelict spacecraft. He flew between the vast metal ribs of a gas giant miner, a-crawl with crab-like beings bereft of pressure suits, the blue-white flare of welding torches shining from between their claws. He saw an ocean in space, floating like a bubble inside a transparent globe tethered to the hull with gossamer cables. Swarms of podcraft maneuvered in precise formations like dancing bees. An atomic sun orbiting the Array brought an artificial dawn, invoking nostalgic memories of the ruins of New York City (though that had been behind several inches of leaded glass while their teacher droned on about the evils of global conflict).

     "Over there," said Nee'Lix. A mushroom-shaped dome was positioned clear of the hull on a slender spire. As the shuttleboat neared, it opened like the eye of a giant monster pondering the approach of prey. "Ahhh Mr. Paris, we need to slow down..."

     "Relax, my furry friend." Jets flared on the thruster rings and the shuttleboat pitched end-over-end; the classic 'skew-flip turnover' to reverse direction so the main engine could be used to decelerate a rocketship. A long burn and some delicate use of the thrusters brought them onto the landing pad with barely a bump.

     It was not their surroundings that were so unusual. The Promenade was recognizable as the former habitat ring of a Big Wheel-type space station, with bulkheads and collision-doors removed to create space for shops and service alcoves; nothing strange on Terran colonies where disused rocketships were routinely adapted as habitations or power sources. Neither was it the noise or the throng that was overwhelming—even the extraterrans on Voyager's crew had visited the overcrowded megacities of Earth. And every spacer (whether they admitted it or not) cultivated a self-image of being a Citizen of the Solar System, equally at ease on Venus, Mars or Terra. But the inhabitants of those planets all shared the same anthropoid form: one head, two eyes, two arms and two legs. It was only amidst this menagerie of aliens that it sunk in just how far they were from home. The crew of Voyager stood gaping like schoolchildren on their first trip to Luna as Nee'Lix scampered around them, pointing out various life-forms.

From ROCKETSHIP VOYAGER by Odon (2020)

Space Trees

I knew about Dyson Trees but I had no idea that there were enough instances of space-going trees in science fiction that they were considering making it into a TV Tropes entry. They certainly are in Orion's Arm.

The idea is to make a space habitat or spacecraft out of a tree. Not out of wood, but out of a living tree. Now, of course you'll have to genetically engineer the tree so it can live in the vacuum of space, but there is certainly is plenty of sunlight in space to make a plant very happy. Add a comet or other source of volatile gases and the tree will have all it needs. Then all you have to do is tinker with its genes so it naturally grows a habitat module suitable for humans to live in, and you are all set.

Now, a tree might not be a durable as a habitat made out of titanium or something, but it does have all the advantages of an organic object. Self-healing, does not need repair technicians or imported spare parts, self-reproducing, that sort of thing. But from a science fiction author's point of view they are a very romantic and fabulous location. Perfect for space elves or other mythological creatures that traditionally live in trees.

A space tree equipped with an engine is actually a type of organic spaceship.


A Dyson tree is a hypothetical genetically-engineered plant (perhaps resembling a tree) capable of growing in a comet, suggested by the physicist Freeman Dyson. Plants could produce a breathable atmosphere within hollow spaces in the comet (or even within the plants themselves), utilising solar energy for photosynthesis and cometary materials for nutrients, thus providing self-sustaining habitats for humanity in the outer solar system analogous to a greenhouse in space or a shell grown by a mollusc.

A Dyson tree might consist of a few main trunk structures growing out from a comet nucleus, branching into limbs and foliage that intertwine, forming a spherical structure possibly dozens of kilometers across.

From the Wikipedia entry for DYSON TREE

Examples of space trees in science fiction include:

  • Manifold: Space by Stephen Baxter (the protagonist finds himself in a dyson tree at one point)
  • The Dirty Pair (in the episode "Run From the Future" there is an outlaw habitat called Nimkasi which is a dyson tree)
  • The Fountain movie (the "space traveler" sections are set in a space-going tree)
  • The Genesis Quest series by Donald Moffitt (he calls them "Space Poplars", the spacecraft version have silver leaves used as organic solar sails)
  • Orion's Arm (dyson trees and dyson tree "forests" are called orwoods)
  • Tree House by Rachel Pollack
  • Comet by Carl Sagan and Ann Druyan (not science fiction, science fact)
  • Absolution Gap by Alastair Reynolds (the "Greenfly" infestation that is depicted taking over the galaxy in Absolution Gap is shown to be billions of self-contained biospheres containing trees and tree-like plants.)
  • Hyperion by Dan Simmons (the Ousters fly around in "Treeships". The main one is of course named Yggdrasil)
  • Vacuum Flowers by Michael Swanwick (in the story "dysonsworlders" have established tree settlements in the Oort Cloud)
  • Tenchi Muyo (the Jurai utilize trees that can live in space as ships)
  • Transhuman Space roleplaying game (includes a dyson tree endeavour on Yggdrasil Station)

Vaguely related tree concepts include: Larry Niven's Stage Trees and Integral Trees, and Marshall Savage's The Millennial Project section Avalon.


An arcology is a titanic multi-level building containing a population of around one hundred thousand people who live, work, and play without ever leaving the building. These were popular in science fiction in the latter half of last century, back in the days when people were frightened that our civilization would be destroyed by runaway overpopulation. Nowadays in industrialized nations, people have started worrying about the opposite. Apparently this has caused science fiction stories about arcologies to become unfashionable.


Arcology, a portmanteau of "architecture" and "ecology", is a field of creating architectural design principles for very densely populated, ecologically low-impact human habitats.

The term was coined by architect Paolo Soleri, who posited that a completed arcology would provide space for a variety of residential, commercial, and agricultural facilities while minimizing individual human environmental impact. These structures have been largely hypothetical insofar as no arcology, even one envisioned by Soleri himself, has yet been built.

The concept has been popularized by various science fiction writers. Authors such as Peter Hamilton in Neutronium Alchemist and Paolo Bacigalupi in The Water Knife explicitly used arcologies as part of their scenarios. They are often portrayed as self-contained or economically self-sufficient.


An arcology is distinguished from a merely large building in that it is designed to lessen the impact of human habitation on any given ecosystem. It could be self-sustainable, employing all or most of its own available resources for a comfortable life: power; climate control; food production; air and water conservation and purification; sewage treatment; etc. An arcology is designed to make it possible to supply those items for a large population. An arcology would supply and maintain its own municipal or urban infrastructures in order to operate and connect with other urban environments apart from its own.

Arcology was proposed to reduce human impact on natural resources. Arcology designs might apply conventional building and civil engineering techniques in very large, but practical projects in order to achieve pedestrian economies of scale that have proven, post-automobile, to be difficult to achieve in other ways.

Frank Lloyd Wright proposed an early version called Broadacre City although, in contrast to an arcology, Wright's idea is comparatively two-dimensional and depends on a road network. Wright's plan described transportation, agriculture, and commerce systems that would support an economy. Critics said that Wright's solution failed to account for population growth, and assumed a more rigid democracy than the U.S.A. actually has.

Buckminster Fuller proposed the Old Man River's City project, a domed city with a capacity of 125,000, as a solution to the housing problems in East St. Louis, Illinois.

Paolo Soleri proposed later solutions, and coined the term 'arcology'. Soleri describes ways of compacting city structures in three dimensions to combat two-dimensional urban sprawl, to economize on transportation and other energy uses. Like Wright, Soleri proposed changes in transportation, agriculture, and commerce. Soleri explored reductions in resource consumption and duplication, land reclamation; he also proposed to eliminate most private transportation. He advocated for greater "frugality" and favored greater use of shared social resources, including public transit (and public libraries).

In popular culture

Most proposals to build real arcologies have failed due to financial, structural or conceptual shortcomings. Arcologies are therefore found primarily in fictional works.

  • One of the earliest examples in literature is William Hope Hodgson's 1912 horror/fantasy novel The Night Land, where the last remnants of humanity survive in two enormous self-contained metal pyramids.
  • Another significant example is the 1981 novel Oath of Fealty by Larry Niven and Jerry Pournelle, in which a segment of the population of Los Angeles has moved into an arcology. The plot examines the social changes that result, both inside and outside the arcology. Thus the arcology is not just a plot device but a subject of critique.
  • In Robert Silverberg's The World Inside, most of the global population of 750 billion lives inside giant skyscrapers, called "urbmons", each of which contains hundreds of thousands of people. The urbmons are arranged in "constellations". Each urbmon is divided into "neighborhoods" of 40 or so floors. All the needs of the inhabitants are provided inside the building – food is grown outside and brought into the building – so the idea of going outside is heretical and can be a sign of madness. The book examines human life when the population density is extremely high.
  • The Maxis computer game SimCity 2000 allows the construction of four different types of arcologies in the future, introducing a wider audience to the concept.
From the Wikipedia entry for ARCOLOGY
Arcology , n.: a concept in which the ideal city is a massive vertical structure, which preserves more of the natural environment, a concept combining architecture and ecology as envisioned by Paolo Soleri
Etymology: arc(hitecture) + (ec)ology definition

Arcology is the architectural discipline described in the page quote. An arcology is the result of said discipline, and is a thing with the following three attributes:
  1. High population density.
  2. Constructed as a single building.
  3. Self-contained in regards to energy, amenities and waste reclamation.

Imagine a skyscraper. Every five or so floors, there is an entire floor dedicated to the inner workings of the floors above it. This is called a deck. The deck level houses all power lines, plumbing mains and anything else that needs to work properly for life to be livable with all the modern conveniences. Now make the skyscraper cover the ground area of a small city or a large town and realize that the decks number in the triple digits. There's the ideal description in a nutshell.

The name of the game here is self-sufficiency. The second attribute above links to the Closed Circle page because the materials required to keep the systems of the building going cannot leave. These processes include food production, waste recycling and environmental refinement (air conditioning and such). People can, in theory, come and go as they please, but the idea is that they don't need to leave. It's worth mentioning that some of the truly huge mega cities in fiction are made up of "arcoplexes," or residentially, commercially, or industrially specialized arcologies that link to each other to create a unified, futuristic ecosystem. After some application of Fridge Logic, City Planet settings almost have to qualify as arcoplexes; otherwise they wouldn't function.

This trope tends towards either extreme hard or soft sci-fi, since the full explanation is pretty complex. It's either going to be explained in detail, or it's going to be handwaved. Depending on who we ask, we may or may not currently have the technology required to make an arcology work in the real world. What is certain is that we don't yet have the political pressure and economy of scale to build one with any reasonable payoff; with current population densities, such a project would be Awesome, but Impractical, thus a fully functional arcology in fiction often requires some Applied Phlebotinum until Technology Marches On comes into effect.

Arcologies appear most often in speculative fiction that tend toward the cynical end of the spectrum, since they are essentially futuristic paradises with a bit of science to back up their justified existence and functionality, and Utopia never holds up under scrutiny. They often appear in video games set After the End or 20 Minutes into the Future, Cyber Punk stories, and most often feature heavily in stories that rely on an environmental or class warfare aesop.

Because they are so insular and answer all of humanity's material needs, arcologies are a great setting for a Wretched Hive masquerading as a Shining City, if not just playing the Layered Metropolis disgustingly straight. If the arcology is actually a Shining City, and a sympathetic character hails from it, expect it to look like a Doomed Hometown eventually. Broken arcologies tend to be the breeding ground for all sorts of nasties, too, since they are no longer fit for human habitation, there's a chance at least some of the sustenance systems still work, and there are at least millions of hiding places. In some Cyber Punk settings, an arcology may be a Shining City in the middle of a Wretched Hive, the arcology's walls forming a neat divide for Urban Segregation.

If the arcology has space engines, it's a Generation Ship. Shares blurred lines with the Mega City, which need only be huge, but sometimes an example of one is an example of both, especially the arcoplex variation. Contrast Hub City, which offers everything you need but a place to call home. Citadel Cities that also qualify as arcologies function extremely well under siege conditions, since dwindling supplies are no longer an issue. Compare and contrast with Layered Metropolis, City on the Water, City in a Bottle, Underground City, Skyscraper City, and Domed Hometown. Even though most of the tropes above are sub-tropes of the Mega City, technically the Arcology is not, since one can exist inside a city without actually being one, itself, even though it usually works out that way. Lastly, see Shining City, which is what an arcology is trying to be from an ecological standpoint, whether it succeeds or not.

(ed note: see TV Trope page for list of examples)

Dome Cities

In science fiction, a domed city is usually what the Encyclopedia of Science Fiction calls a "Keep." It is basically a glorified gated community. The citizens live inside the dome in a paradise, while the dome keeps out the riff-raff / less-than-perfect weather / annoying bugs and dirty animals / post-apocalyptic wasteland / brain-eating zombies / global plague / or other undesirables. The idea is to exaggerate the contrast between the marvelous lives of the privileged inside and the nasty-brutish-and-short lives of the unfortunates living outside.

And in science fiction with the standard morality-play plot, the fun generally starts when something from outside manages to sneak in.

Cities that use domes to keep out nasty weather are a contrast with Stratified Cities where the elite upper-crust get natural weather while the ghetto dwellers live in dark shadows under the mega-skyscrapers or even underground.

And as a side note, undersea cities traditionally are under domes as well. Since water is so hard for humans to breath.


A domed city is a hypothetical structure that encloses a large urban area under a single roof. In most descriptions, the dome is airtight and pressurized, creating a habitat that can be controlled for air temperature, composition and quality, typically due to an external atmosphere (or lack thereof) that is inimical to habitation for one or more reasons. Domed cities have been a fixture of science fiction and futurology since the early 20th century, and may be situated on Earth, a moon or other planet.


It is not clear exactly when the concept of a domed city first appeared. The phrase "domed city" had come into use by the 19th century in a different sense, meaning a skyline with dome-topped buildings. One catalogue of early science fiction mentions the 1881 socialist and white supremacist fantasy Three Hundred Years Hence by British author William Delisle Hay (not to be confused with an earlier novel of the same title, by Mary Griffith). Hay's book describes a future civilization where most of humanity lives in glass-domed cities beneath the sea, allowing the surface of the earth to be used primarily for agriculture. Several examples from the early 20th century are also listed.

In fiction

Authors used domed cities in response to many problems, sometimes to the benefit of the people living in them and sometimes not. The problems of air pollution and other environmental destruction are a common motive, particularly in stories of the middle to late 20th century. As in the Pure trilogy of books by Julianna Baggott. In some works, the domed city represents the last stand of a human race that is either dead or dying. The 1976 film Logan's Run shows both of these themes. The characters have a comfortable life within a domed city, but the city also serves to control the populace and to ensure that humanity never again outgrows its means.

The domed city in fiction has been interpreted as a symbolic womb that both nourishes and protects humanity. Where other science fiction stories emphasize the vast expanse of the universe, the domed city places limits on its inhabitants, with the subtext that chaos will ensue if they interact with the world outside.

In some works cities are getting "domed" to quarantine its inhabitants.

  • The Bubble, a 1966 film
  • Manhattan Transfer, a 1993 novel, features Manhattan and a host of alien cities, each under its own dome, all set aboard an enormous starship.
  • The Truman Show (1998), set on an island covered by a dome
  • Girls, a 2005 comic book series
  • In the 2006 anime series Ergo Proxy domed cities are smart city-infrastructures created for the survival of mankind in the post-apocalyptic age. They are designed to be self-sufficient and to support a small controlled population of people and their robot companions and entourages.
  • The Simpsons Movie, a 2007 film of the TV series The Simpsons
  • Power Rangers RPM takes place in a domed city called Corinth, which shields humanity from polluting machines of the Venjix network.
  • Under the Dome, a 2013 TV series based on the 2009 novel of the same name by Stephen King.
  • In the 2013 science fiction video game Crysis 3 the private military company C.E.L.L. erected giant domes around cities – including New York City – in order to kill off the rest of the hostile aliens from the game series. The domes cause a rainforest atmosphere in the urban environments and have the hidden purpose to help C.E.L.L. in their conquest for world domination through technology.

Engineering proposals

During the 1960s and 1970s, the domed city concept was widely discussed outside the confines of science fiction. In 1960, visionary engineer Buckminster Fuller described a 3 km geodesic dome spanning Midtown Manhattan that would regulate weather and reduce air pollution. A domed city was proposed in 1979 for Winooski, Vermont and in 2010 for Houston.

In order to test whether an artificial closed ecological system was feasible, Biosphere 2 (a complex of interconnected domes and glass pyramids) was constructed in the late 1980s. Its original experiment housed eight people and remains the largest such system attempted to date.

In 2010, a domed city known as Eco-city 2020 of 100,000 was proposed for the Mir mine in Siberia. In 2014, the ruler of Dubai announced plans for a climate-controlled domed city covering an area of 48 million square feet (4.5 square kilometers). A domed city called the Canop-E has been envisaged by some Indian experts. It will be a 1 urban settlement under a single roof which will generate Solar Energy, harvest rainwater and harness wind energy. It will be capable of controlling temperature and internal environment and promote sustainable living.

From the Wikipedia entry for DOMED CITY

      The City now! New York City in which he lived and had his being. Larger than any City but Los Angeles. More populous than any but Shanghai. It was only three centuries old. To be sure, something had existed in the same geographic area before then that had been called New York City. That primitive gathering of population had existed for three thousand years, not three hundred, but it hadn’t been a City.

     There were no Cities then. There were just huddles of dwelling places large and small, open to the air. They were something like the Spacer’s Domes, only much different, of course. These huddles (the largest barely reached ten million in population and most never reached one million) were scattered all over Earth by the thousands. By modern standards, they had been completely inefficient, economically. Efficiency had been forced on Earth with increasing population. Two billion people, three billion, even five billion could be supported by the planet by progressive lowering of the standard of living. When the population reaches eight billion, however, semistarvation becomes too much like the real thing. A radical change had to take place in man’s culture, particularly when it turned out that the Outer Worlds (which had merely been Earth’s colonies a thousand years before) were tremendously serious in their immigration restrictions.

     The radical change had been the gradual formation of the Cities over a thousand years of Earth’s history. Efficiency implied bigness. Even in Medieval times that had been realized, perhaps unconsciously. Home industry gave way to factories and factories to continental industries. Think of the inefficiency of a hundred thousand houses for a hundred thousand families as compared with a hundred-thousand-unit Section; a bookfilm collection in each house as compared with a Section film concentrate; independent video for each family as compared with video-piping systems. For that matter, take the simple folly of endless duplication of kitchens and bathrooms as compared with the thoroughly efficient diners and shower rooms made possible by City culture.

     More and more the villages, towns, and “cities” of Earth died and were swallowed by the Cities. Even the early prospects of atomic war only slowed the trend. With the invention of the force shield, the trend became a headlong race.

     City culture meant optimum distribution of food, increasing utilization of yeasts and hydroponics. New York City spread over two thousand square miles and at the last census its population was well over twenty million. There were some eight hundred Cities on Earth, average population, ten million. Each City became a semiautonomous unit, economically all but self-sufficient. It could roof itself in, gird itself about, burrow itself under. It became a steel cave, a tremendous, self-contained cave of steel and concrete. It could lay itself out scientifically. At the center was the enormous complex of administrative offices. In careful orientation to one another and to the whole were the large residential Sections connected and interlaced by the expressway and the locaiways. Toward the outskirts were the factories, the hydroponic plants, the yeast-culture vats, the power plants. Through all the melee were the water pipes and sewage ducts, schools, prisons and shops, power lines and communication beams.

     There was no doubt about it: the City was the culmination of man’s mastery over the environment. Not space travel, not the fifty colonized worlds that were now so haughtily independent, but the City.

     Practically none of Earth’s population lived outside the Cities. Outside was the wilderness, the open sky that few men could face with anything like equanimity (people who grew up in a City suffer from agoraphobia. They are terrified if there is not an opaque roof over their heads). To be sure, the open space was necessary. It held the water that men must have, the coal and the wood that were the ultimate raw materials for plastics and for the eternally growing yeast. (Petroleum had long since gone, but oil-rich strains of yeast were an adequate substitute.) The land between the Cities still held the mines, and was still used to a larger extent than most men realized for growing food and grazing stock. It was inefficient, but beef, pork, and grain always found a luxury market and could be used for export purposes. But few humans were required to run the mines and ranches, to exploit the farms and pipe the water, and these supervised at long distance. Robots did the work better and required less.

From THE CAVES OF STEEL by Isaac Asimov (1953)

      “When you’re on the ground, you can’t be sure you see to the top of it. It just sort of fades away when you look up at it.”
     “You notice what it was built of?” asked Doc.
     “Stone,” said Hutch.
     “I thought so, too,” said Doc. “But it isn’t. You remember those big apartment mounds we ran into in that insect culture out on Suud?”

     We all remembered them, of course. We’d spent days trying to break into them because we had found a handful of beautifully carved jade scattered around the entrance of one of them and we figured there might be a lot of it inside. Stuff like that brings money. Folks back in civilization are nuts about any kind of alien art and that jade sure enough was alien.

     We’d tried every trick that we could think of and we got nowhere. Breaking into those mounds was like punching a feather pillow. You could dent the surface plenty, but you couldn’t break it because the strength of the material built up as pressure compressed the atoms. The harder you hit, the tougher it became. It was the kind of building material that would last forever and never need repair and those insects must have known they were safe from us, for they went about their business and never noticed us. That’s what made it so infuriating.

From JACKPOT by Clifford Simak (1956)

      Matello slammed his goblet on the table. “Not to make gold, you may be sure! This book is bait. I need it to help me to get a man inside the Duke of Koss’s Aegis. Do you understand me?”
     (Rachad Caban says) “No, my lord.”
     Matello sighed. “I feared not.”

     “What is this ‘Aegis,’ my lord?”
     “An aegis,” Matello answered, with self-conscious patience, “is an impregnable fortress. It is built of adamant, a substance which is absolutely indestructible, and once inside it there is no known weapon that can harm you, and no way that the fortress can be breached. Now, as to the Duke of Koss, who lives in its protection—” Suddenly Matello rose to his feet. “Let someone else give you an indication of his character.”

     Beckoning to Rachad, he strolled to the far end of the hall, stopping at the iron tank. As he followed, the fog of yellow powder stung Rachad’s nostrils and made him cough. He looked into the low tank, and recoiled with a gasp.
     “Don’t be afraid,” the baron murmured. “He’s as civilized as you or I.”
     Rachad guessed that the tank was deeper than it appeared from the outside and was set into the floor. It was filled to within a foot of the brim with fine yellow powder, resembling flowers of sulphur. The powder was waving and rippling. “Swimming” just beneath its surface was an undulating shape.

     “Flammarion!” Matello said in a loud voice. “I have with me the young man I mentioned.”
     The swimming shape surfaced. The creature was gray in color and resembled a stingray, with a waving, flapping cape. From beneath it came slim tentacles which tapped the sides of the tank, but Rachad could not properly see what else the cape hid. He forced himself to be calm as the beast flopped part of itself over the side of the trough, splashing out gouts of bright yellow powder.
     “I sense you, humans. Greetings, Rachad Caban.”
     “Er—greetings,” Rachad stuttered. The creature’s voice was soft and human-sounding, yet somehow larger than a man’s without being louder.

     “This is Flammarion,” Matello said to Rachad, “a master builder from the other side of the galaxy. He it was who built the duke’s Aegis, long ago, and he and I are now united in a common purpose—somehow to break into that aegis. It is an ambition not altogether unique to us, for the duke has many enemies.”
     He turned to the tank. “Tell Caban your story, Flammarion. It is best he should know the background to his mission.”

     There was a pause, while the alien creature flapped and stirred in the powder-bath. “It is a sad tale, a pathetic tale, one that can only bring bathos and pity,” the voice said mournfully. “I am an acknowledged expert in the building of aegises. I alone know the secret of adamant, a material impervious to any weapon, unaffected even by alkahest, the universal solvent. No gun, arbalest or sonic trembler can break it, no acid can corrode it. It deadens even the shriek of Vurelian war trumpets, whose vibrations pass through stone and steel to kill those within.”
     Flammarion paused again and went surging through the powder. “Thinking to employ my talents in foreign parts of the galaxy, I traveled to that region where humans dwell. Here I was commissioned by the Duke of Koss to build an aegis for him. I labored mightily, constructing, I believe, the best example of my skills so far. Finally the work was finished, the duke took up residence, and after a decent interval to allow inspection, I presented myself before the gate to collect my fee: two tons of heavenly water, a rare commodity much prized by my kind.”
     The voice of the alien became burdened with dole. “His answer was direct and most unkind. ‘If the Aegis is truly invulnerable as claimed by you and specified by contract, you have no means by which to enter and extract payment. You cannot hurt me; here I shall remain forever. Begone!’ Oh, cruel injustice! Since then I have remained nearby, trying by this stratagem and that to force payment from my client.”

(ed note: Caban, carrying a priceless book of alchemical lore, convinces the Duke of Koss to open the Aegis gate and let him in. A couple of weeks later by a clever stratagem, fools the guards into opening the Aegis gate. The soldiers of Baron Matello storm inside and capture the fortress.)

     Flammarion, moving with surprising agility by means of his warping wings, attached himself to the party led by Baron Matello and proved as eager as any. But his search had only one object—the Duke of Koss himself, the man who had spent a lifetime as his creditor.
     They eventually found the defeated duke deep down in the fortress. He lay limply on a samite couch, a servant girl dabbing at his brow with scented water. He seemed to be in a state of collapse.

     He stirred feebly when Matello and his men burst into the chamber. His face was fully as pale and deathlike as the face of the homunculus that had recently impersonated him. “Who are these strangers who disturb my peace?” he murmured, his voice so faint as to be barely audible. “Vandals, despoilers, desecrators of my pleasure….”
     “We are here because you failed to do your duty, Koss!” Baron Matello stormed.

     From behind him Flammarion came forward. He reared up over the supine noble like a threatening cobra. “Now is the time to remind you of our contract, Your Grace!” he exclaimed, his voice vibrant with passion.
     “What strange beast is this?” the duke queried breathlessly. “Ah yes, the builder of my retreat, of my cosmos.”
     “My fee! I am here to collect my fee, unpaid for all these years!”
     “But the Aegis was not invulnerable, master builder,” the duke replied in a pained whisper. “No payment is due.”
     “Not invulnerable?” Matello demanded incredulously.
     “Why, no… as is attested by your presence here….” The duke smiled faintly. Then he uttered a sigh.

     His head suddenly lolled.
     “He took poison,” the girl told them. “It takes a few minutes to work.”
     Matello grabbed the duke’s head by the hair and turned it so as to lift an eyelid with his thumb. Then, with a grunt, he let it drop.
     “Well that’s that. Don’t worry, Flammarion, there’s plenty of stuff here. I’ll see you get your reward.”

     Flammarion’s response was dolorous and labored. “But the logic of his argument is inescapable,” he droned. “To collect payment, I must first force access to the Aegis; yet once that is done the terms of the contract are broken. How completely the old duke tricked me! I can accept no fee.”
     “What are you worried about? Take what you want anyway.”
     “No. The ethic of my craft will not permit sharp, practice. What an ill day it was when I ventured into Maralia! I have labored in vain!”

From STAR WINDS by Barrington Bayley (1978)

(ed note: in Poul Anderson's novel, Brain Wave, a cosmic accident raises the IQ of everybody on Earth by a factor of five. One side effect is that their language becomes information dense.)

      Overhead, there was a dull blue wash of luminance across the sky, flickering and glimmering on the edge of visibility. The Empire State Building was crowned with a burning sphere like a small sun come to rest, and the wandering air held a faint tingle of ozone. The two men sat quietly, resting, smoking the tobacco which had again become minutely available, Mandelbaum’s pipe and Rossman’s cigarette like two ruddy eyes in the twilit room. They were waiting for death.

     “Wife,” said Rossman with a note of gentle reproach. It could be rendered as: (I still don’t see why you wouldn’t tell your wife of this, and be with her tonight. It may be the last night of your lives.)
     “Work, city, time,” and the immemorial shrug and the wistful tone: (We both have our work to do, she at the relief center and I here at the defense hub. We haven’t told the city either, you and I and the few others who know. It’s best not to do so, eh?) We couldn’t have evacuated them, there would have been no place for them to go and the fact of our attempting it would’ve been a tip-off to the enemy, an invitation to send the rockets immediately. Either we can save the city or we can’t; at the moment, there’s nothing anyone can do but wait and see if the defense works. (I wouldn’t worry my Liebchen—she’d worry on my account and the kids’ and grandchildren’s. No, let it happen, one way or the other. Still I do wish we could be together now, Sarah and I, the whole family—) Mandelbaum tamped his pipe with a horny thumb.
     (The Brookhaven men think the field will stop the blast and radiation), implied Rossman. We’ve had them working secretly for the past month or more, anticipating an attack. The cities we think will be assailed are guarded now—we hope. (But it’s problematic. I wish we didn’t have to do it this way.)
     “What other way?” We knew, from our spies and deductions, that the Soviets have developed their intercontinental atomic rockets, and that they’re desperate. Revolution at home, arms and aid being smuggled in to the insurgents from America. They’ll make a last-ditch attempt to wipe us out, and we believe the attack is due tonight. But if it fails, they’ve shot their bolt. It must have taken all their remaining resources to design and build those rockets. “Let them exhaust themselves against us, while the rebels take over their country. Dictatorship is done for.”

     There was a thin buzz from the telecom unit beside Mandelbaum. He reached over and flipped the switch. There was a sudden feeling of weariness in him. He ought to be tense, jittering with excitement, but he only felt tired and hollow.
     The machine clicked a few signals: “Space station robot reports flight of rockets from Urals. Four are due at New York in about ten minutes.”
     “Ten minutes!” Rossman whistled. “They must have an atomic drive.”

     “No doubt.” Mandelbaum dialed for Shield Center in the Empire State Building. “Brace your machinery, boys,” he said. “Ten minutes to go.”
     “How many?”
     “Four. They must figure on our stopping at least three, so they’ll be powerful brutes. Hydrogen-lithium warheads, I imagine.”
     “Four, eh? Okay, boss. Wish us luck.”
     “Wish you luck?” Mandelbaum grinned crookedly.

     The city had been told that the project was an experiment in illumination. But when the blueness strengthened to a steady glow, like a roof of light, and the sirens began to hoot, everyone must have guessed the truth. Mandelbaum thought of husbands clutching wives and children to them and wondered what else might be happening.
     “Ah, well, no need to cry into it,” answered Mandelbaum. “The screen will hold. It’s the same kind of force that holds atomic nuclei together—nothing stronger in the universe.
     “Those rockets—” (They do represent something. They are beautiful things, you know, clean and shining, built with utter honesty. It took many patient centuries to reach the point where they could be forged. The fact that they carry death for us is incidental.)
     (I don’t agree.) Mandelbaum chuckled, a sad little sound in the great quiet around him.
     There was a luminous-dialed clock in the room. Its sweep-second hand went in a long lazy circle, once around, twice around, three times around. The Empire State was a pylon of darkness against the dull blue arc of sky. Mandelbaum and Rossman sat drinking, lost in their own thoughts.

     There was a glare like lightning all over heaven, the sky was a sudden incandescent bowl. Mandelbaum covered his dazzled eyes, letting the goblet fall shattering to the floor. He felt the radiance on his skin like sunshine, blinking on and off. The city roared with thunder.

     —two, three, four.

     Afterward there was another stillness, in which the echoes shuddered and boomed between high walls. A wind sighed down the empty streets, and the great buildings shivered slowly back toward rest.
     “Good enough,” said Mandelbaum. He didn’t feel any particular emotion. The screen had worked, the city lived.

From BRAIN WAVE by Poul Anderson (1954)

      "I could certainly see the signs in my time," she said, "and I'd be surprised if they weren't already visible in yours. If I was asked to provide a single word for what started the change, I'd give one that I've never seen quoted: glass. Before people had glass, there was a time when they didn't have buildings at all. They lived outside, in the middle of whatever was out there—animals of all sizes, from fleas to elephants. They might not have liked it, but they couldn't do a thing about it. As time went on people learned to make buildings and could live indoors. But if you wanted to see what you were doing, there had to be holes in the walls to let in light. You could make the holes small, so the elephants and wolves and bears couldn't get in. But there was no way of making the holes big enough to let light in, yet small enough to keep insects and spiders and wood lice and centipedes out. People still expected to live in the middle of bugs of all kinds. So they squashed them, or encouraged them—spiders will keep your house free of flies—or just put up with them.

     "But then cheap, good-quality glass became available. You could make windows that let the light in and kept the bugs out. And that's when people started to think that spiders and cockroaches and ants were 'dirty,' and even 'unnatural.' I've known women who would scream if they found a decent-sized spider in their bathroom. And as for doing this—"

     She reached down to the tall grass at their feet, and stood up again holding a big grasshopper gently in her cupped hands. "I knew people who wouldn't touch a harmless bug like this, not if you paid them. Don't you think it's peculiar, even the word dirty changed its meaning. We're walking on dirt. Dirt is everywhere. It's totally natural. The ground is made of dirt. But when you live in a totally artificial environment, shielded from the outside, you never see real earth. 'Dirty' things become completely unnatural, and you avoid them. The good news is, when people wanted less and less to go outside, because it was full of beetles and gnats and worms and earwigs and leeches, they were willing to let the surface become more like the way it used to be before humans took over." She bent down, released the grasshopper, and pointed away to their left. "Not just grasshoppers and bees and flies, either. Go twenty to thirty kilometers that way, you'll find gazelles and wildebeest and cheetahs. Maybe lions, too."

From TOMORROW AND TOMORROW by Charles Sheffield (1997)

“It must be a beacon, a marker—but for whom—run by whom—?”

“Must it be run by anyone?” asked Rolth thoughtfully. “Remember Tantor—”

Tantor, the sealed city. Its inhabitants had been overwhelmed by a ghastly plague two centuries ago. Yes, he recalled Tantor well. Once he had flown above the vast bubble which enclosed it in an eternal prison for the safety of the galaxy, and had watched the ancient machines going about their business below, running a city in which no living thing walked or ever would walk again. Tantor had had its beacons too, and its appeals for help streaming into the skies mechanically long after the hands which had set them going had been dust. Behind those hills ahead might well rest another Tantor—it would explain the puzzle of a fair but deserted world.

From STAR RANGERS by Andre Norton, 1953.
Collected in STAR SOLDIERS (2001), currently a free eBook in the Baen free library.

Floating Cities

When the ultra-rich upper crust wants to really look down on the lower classes, nothing can beat living in a floating city. Or even if there are no miserable peons living in slums below, the view will still be spectactular. If there are slums, the combination of floating city above and ghetto below is called a Stratified City.


Retreating to the net, she scanned for free feelie casts, finding a 3V ad for a resort and retirement aerostat in Typhon’s upper atmosphere (Typhon is a gas giant). Floating like a huge transparent bubble several klicks across, the aerostat hung from a giant balloon of heated hydrogen, suspended amid brown clouds of ammonium hydrosulfide hundreds of klicks above a grey-white sea of water ice clouds. Within the aerostat’s protective bubble was a free-form world, where beautiful people flitted between aerial hamlets on gossamer wings and skycycles. Fairyland to a child raised in cubicals and corridors, breathtakingly wonderful no matter how often she felt it. She blended with the ad, riding a skycycle with wind streaming in a cool rush of feeling over her face, weirdly refreshing. She peddled along, dodging skyships, pleasure barges, and colorful homes floating like open flowers complete with hanging gardens and rooftop landing pads. Aerostat technology was used by the first settlers to terraform Oceania and the inner worlds, then introduced to Typhon to provide living space in the outer system. Ice mining and terraforming left colonies scattered about Typhon living off local resources and gravity advantage—not everyone could pick up and move to the wonderful new inner worlds. Kay was having her troubles just getting to The Hub.

Shooting through waterfall rainbows, she skimmed the surface of the warm ballast lake at the bottom of the bubble, feeling the splash of spray on her feet, all without fear of crashing—this was just a commercial. To prove it she pulled back on the skycycle and did a perfect inside loop right into the lake.

Soon as she hit the water she was swimming, no longer aboard a skycycle, but nude, wearing only swim fins, goggles, and a rebreather. Warm oxygenated water turned her into an aquatic creature, gliding at will over sunlit sand through schools of tiny silver fish, swimming effortlessly despite never having been in water deeper than a sponge bath—all thanks to the power of advertising.

From RING RATS by R. Garcia y Robertson (2002)

Undersea Cities

Come to inner space! Undersea cities are a time-honored trope in science fiction. And cinematically dramatic to boot. A domed city on the ocean floor with zillions of fish, squids, and other sea life swimming by; how cool is that?

In older science fiction, a common trope is for oceanic explorers on Terra to stumble over the lost continent of Atlantis. Which is typically inhabited by humans descended from the original inhabitants, who either have learned how to breath water or who quickly became good at building air-tight underwater cities. In Lester del Rey's Attack from Atlantis the Atlanteans accidentally discover how to make unreasonably strong force fields, which is a good trick since at the time they hadn't discovered electricity yet.

Most science fiction movies featuring underwater cities are pretty abysmal (sorry). These include City Beneath The Sea, City Under the Sea, Captain Nemo and the Underwater City, and The Underwater City. Oh, and in Star Wars there is Otoh Gunga, but I didn't want to dredge up any unpleasant memories.

"City Beneath The Sea" was obviously a poorly disguised pilot for a proposed TV series. Sank without a trace. The TV show seaQuest DSV lasted two and one-half seasons before they pulled the plug. A few episodes featured underwater colonies. And there was that old animated series Sealab 2020.

Don't forget the underwater city of Rapture in the video game BioShock.

The hapless protagonists in the novel Dome have to learn real quick how to convert their temporary underwater lab off the coast of Hawaii into an underwater colony. It seems that the political situation on the surface deteriorated rapidly, and a global war using biological weapons had rendered life above water impossible for the foreseeable future.

The people in Frederik Pohl and Jack Williamson's Undersea Trilogy live in underwater cities with magic force fields. The novel series is sort of like Robert Heinlein's Space Cadet set underwater. In Kenneth Bulmer's City Under the Sea the protagonist discovers what a cut-throat industry underwater food production is.

For a more scientifically accurate underwater colony there is Hal Clement's Ocean On Top. Predictably, since Hal Clement has a reputation for writing hard science fiction. The colonists use geothermal power, and live in a special oxygenated liquid to cope with the ocean pressure.

Back in the day there were a few underwater cities set on the planet Venus, because back in the day one of the leading astronomical theories was that Venus was totally covered in oceans (a "pelagic planet"). Of course back then astronomers thought Mars had canals. The classic was the Keeps series by Henry Kuttner and C. L. Moore. Others include Isaac Asimov's Lucky Starr and the Oceans Of Venus and Roger Zelazny's The Doors of His Face, the Lamps of His Mouth.

There have been a few novels with extensive underwater research labs in the oceans of Europa or other Jovian moons, ever since scientist figured out the Galilean satellites had sub-ice oceans and might even have black-smoker type ecosystems.


      Aphrodite is the largest city on Venus, with a population of over a quarter of a million.
     With the Venus Marvel still a mile away, the sea about it was lit into green translucence by Aphrodite’s lights. In the eerie luminosity the. dark, sleek shapes of the rescue vessels, which had been sent out to meet them after radio contact had been established, could be plainly made out. They slipped along, silent companions.
     As for Lucky and Bigman, it was their first sight of one of Venus’s underwater domed cities. They almost forgot the unpleasantness they had just passed through, in their amazement at the wonderful object before them.
     From a distance it seemed an emerald-green, fairyland bubble, shimmering and quivering because of the water between them. Dimly they could make out buildings and the structural webbing of the beams that held up the city dome against the weight of water overhead.
     It grew larger and glowed more brightly as they approached. The green grew lighter as the distance of water between them grew less. Aphrodite became less unreal, less fairylandish, but even more magnificent.
     Finally they slid into a huge air lock, capable of holding a small fleet of freighters or a large battle cruiser, and waited while the water was pumped out. And when that was done, the Venus Marvel was floated out of the lock and into the city on a lift field.

     The Green Room of the Hotel Bellevue-Aphrodite was just that. The quality of the lighting and the shimmer of it gave the tables and guests the appearance of being suspended beneath the sea. The ceiling was an inverted bowl, below which there turned slowly a large aquarium globe, supported by cunningly placed lift beams. The water in it was laced with strands of Venusian seaweed and in among it writhed colorful “sea ribbons,” one of the most beautiful forms of animal life on the planet.
     Then the music started, the domed ceiling gradually came to glowing life, and the aquarium globe began its gentle spinning. The sea ribbons were of different lengths, varying from tiny threads two inches long to broad and sinuous belts that stretched a yard or more from end to end. They were all thin, thin as a sheet of paper. They moved by wriggling their bodies into a series of waves that rippled down their full length.
     And each one fluoresced; each one sparkled with colored light. It was a tremendous display. Down the sides of each sea ribbon were little glowing spirals of light: crimson, pink, and orange; a few blues and violets scattered through; and one or two striking whites among the larger specimens. All were overcast with the light-green wash of the external light. As they swam, the lines of color snapped and interlaced. To the dazzled eye they seemed to be leaving rainbow trails that washed and sparkled in the water, fading out only to be renewed in still brighter tints.

     Lucky handled the trim subsea craft with growing expertness as he learned the touch of the controls and began to get the feel of the sea about them.
     For the first hour Bigman had been scarcely aware of the microwaves and the object of their search. He had been lost in the spectacle to be seen from the portholes.
     Venusian subsea life is phosphorescent, and the black ocean depths were dotted with colored lights thicker than the stars in space, larger, brighter, and most of all, moving. Bigman squashed his nose against the thick glass and stared, fascinated.
     Some of the life forms were little round splotches, whose movement was a slow ripple. Others were darting lines. Still others were sea ribbons of the type Lucky and Bigman had seen in the Green Room.
     Lucky joined him after a while. He said, “If I remember my xenozoology “
     “Your what?”
     “That’s the study of extraterrestrial animals, Bigman. I’ve just been looking through a book on Venusian life. I left it on your bunk in case you want to look at it.”
     “Never mind. I’ll take it second hand from you.”
     “All right. We can start with those little objects. I think that represents a school of buttons.”
     “Buttons?” said Bigman. Then, “Sure, I see what you mean.”
     There were a whole series of yellow ovals of light moving across the black field visible through the porthole. Each had black markings on it in the form of two short parallel lines. They moved in brief spurts, settled down for a few moments, then moved again. The dozens in view all moved and rested simultaneously, so that Bigman had the queerly swimming sensation that the buttons weren’t moving at all, but that every half minute or so the ship itself lurched.
     Lucky said, “They’re laying eggs, I think.” He was silent for a long moment, then said, “Most of these things I can’t make out. Wait! That must be a scarlet patch there. See it? The dark red thing with the irregular outline? It feeds on buttons. Watch it.”
     There was a scurrying among the yellow blotches of light as they became aware of the swooping predator, but a dozen buttons were blotted out by the angry red of the scarlet patch. Then the patch was the only source of light in the porthole’s field of vision. On all sides of it, buttons had scattered away.
     Pre-eminent among them were arrow fish of all sizes. Each had a straight white line of phosphorescence that marked its backbone (it wasn’t a backbone really, but merely an unjointed rod of horny substance). At one end of that white line was a pale yellow V that marked the head. To Bigman it looked indeed as though a countless swarm of animated arrows were swarming past the ship, but in imagination he could see their needle-rimmed jaws, cavernous and ravenous.


Space Oceans


      "I should just give up and take a running dive back there."
     His metal-dad arm gestured toward the station and its comfortable spin hanging half a mile away. Technically the wheel-shaped structure io its synchronous orbit was above the two men, but it took careful observing to decide which way was really "up."
     "You wouldn't make it," Silbert replied. "If you had solid footing for a jump you might get that far, since twenty feet a second would take you away from here permanently. But speed and velocity are two different animals. I wouldn't trust even myself to make such a jump in the right direction-and I know the vectors better than you do by a long shot. Which way would you jump? Right at the station? Or ahead of it, or behind it? And which is ahead and which is behind? Do you know?"
     The computerman's arm waved again, this time at the surface underfoot, and he tried to stamp on it at the same moment. The latter gesture produced odd results. The material, which looked a little like clear jelly, gave under the boot but bulged upward all around it. The bulge moved outward very slowly in all directions, the star patterns reflected in the surface writhing as it passed. As the bulge's radius increased its height lessened, as with a ripple spreading on a pond. It might have been an ultra-slow motion picture of such a ripple, except that it did not travel far enough. It died out less than two yards from Bresnahan's foot, though it took well over a minute to get that far.
     "Yeah, I know what you mean. Walking on water was kind of a divine gift, wasn't it? Well, you can always remember we're not right on the water. There's the pressure film, even if you can't see it."
     They had reached a disk of metal some thirty feet in diameter, projecting about two feet from the surface of the satellite. It continued below the surface for a distance which refraction made hard to estimate.
     Its water line was marked by a ring of black, rubbery-looking material where the pressure film adhered to it. The men had been quite close to it when they landed on Raindrop's surface a few minutes before. But it is hard to make out landscape details on a water surface under a black, starfilled sky; the reflection underfoot is not very different from the original above. A five-mile radius of curvature puts the reflected images far enough down so that human depth perception is no help.
     Waves betrayed themselves, of course, and might have shown the lock's location—but under a gravitational acceleration of about a tenth of an inch per second squared, the surface waves raised by space-suit boots traveled much more slowly than the men who wore them. And with their high internal energy losses they didn't get far enough to be useful.
     As a result, Bresnahan had not realized that the lock was at hand until they were almost upon it. Even Silbert, who had known about where they would land and could orient himself with Raindrop's rotation axis by celestial reference features, did not actually see it until it was only a few yards away.
     "This is the place, all right," he acknowledged. "That little plate near the edge is the control panel. We'll use the manhole; no need to open the main hatch as we do when it's a matter of cargo."
     He bent over—slowly enough to keep his feet on the metal—and punched one of the buttons on the panel he had pointed out. A tiny light promptly flashed green, and he punched a second button.
A yard-square trap opened inward, revealing the top of a ladder. Silbert seized the highest rung and pulled himself through the opening head first—when a man weighs less than an ounce in full space panoply it makes little real difference when he elects to traverse a ladder head downward. Bresnahan followed and found himself in a cylindrical chamber which took up most of the inside of the lock structure. It could now be seen that this must extend some forty feet into the body of Raindrop.     At the inner end of the compartment, where curved and flat walls met, a smaller chamber was partitioned off. Silbert dove in this direction.
     "This is a personnel lock," he remarked. "We'll use it; it saves flooding the whole chamber."
     "We can use ordinary spacesuits?"
     "Might as well. If we were going to stay long enough for real work, we'd change—there is local equipment in those cabinets along the wall. Spacesuits are safe enough, but pretty clumsy when it comes to fine manipulation."
     The spaceman opened the door manually—there seemed to be no power controls involved—and the two entered a room some five feet square and seven high. Operation of the lock seemed simple; Silbert closed the door they had just used and turned a latch to secure it, then opened another manual valve on the other side of the chamber. A jet of water squirted in and filled the space in half a minute. Then he simply opened a door in the same wall with the valve, and the spacesuited figures swam out.
     This was not as bad as walking on what had seemed like nothingness. Bresnahan was a good swimmer and experienced free diver, and was used to being suspended in a medium where one couldn't see very far.
     The water was clear, though not as clear as that sometimes found in Earth's tropical seas. There was no easy way to tell just how far vision could reach, since nothing familiar and of known size was in view except for the lock they had just quitted. There were no fishes—Raindrop's owners were still debating the advisability of establishing them there—and none of the plant life was familiar, at least to Bresnahan. He knew that the big sphere of water had been seeded by "artificial" life forms — algae and bacteria whose genetic patterns had been altered to let them live in a "sea" so different from Earth's.

     Raindrop was composed of the nuclei of several small comets, or rather what was left of those nuclei after some of their mass had been used in reaction motors to put them into orbit about the earth. They had been encased in a polymer film sprayed on to form a pressure seal, and then melted by solar energy, concentrated by giant foil mirrors.
     Traces of the original wrapping were still around, but its function had been replaced by one of the first tailored life forms to be established after the mass was liquid. This was a modification of one of the gelatin-capsule algae, which now encased all of Raindrop in a microscopically thin film able to heal itself after small meteoroid punctures, and strong enough to maintain about a quarter of an atmosphere's pressure on the contents. The biological engineer who had done that tailoring job still regarded it as his professional masterpiece.
     The methane present in the original comet material had been oxidized by other bacteria to water and carbon dioxide, the oxygen of course coming from normal photosynthesis. A good deal of the ammonia was still present, and furnished the principal reason why genetic tailoring was still necessary on life forms being transplanted to the weightless aquarium.
     The men were drifting very slowly away from the lock, though they had stopped swimming, and the younger one asked,
     "How do we find our way back here if we get out of sight?"
     "The best trick is not to get out of sight. Unless you want to examine the core, which I've never done, you'll see everything there is to see right here. There is sonic and magnetic gear—homing equipment—in your suit if you need it, though I haven't checked you out on its use. You'd better stay with me. I can probably show you what's needed. Just what points do you think Weisanen wants covered?"
     "Well, he knows the general physical setup—temperature, rotation, general current pattern, the nature of the skin. He knows what's been planted here at various times; but it's hard to keep up to date on what's evolved since. These tailored life forms aren't very stable toward mutation influences, and a new-stocked aquarium isn't a very stable ecolotical environment. He'd. want to know what's here now in the way of usable plants, I suppose. You know the Agency sold Raindrop to a private concern after the last election. The new owners seem willing to grant the importance of basic reaearch, but they would sort of like a profit to report to the stockholders as well"
     "Amen. I'm a stockholder."
     "Oh? Well, it does cost something to keep supply ships coming up here, and—"

     "Well, I guess Weisanen owns a bigger piece of Raindrop than you do. Anyway, he's my boss, whether he's yours or not, and he wants a report from me, and I can't see much to report on. What life is there in this place besides the stuff forming the surface skin?"
     "Oh, lots. You just aren't looking carefully enough. A lot of it is microscopic, of course; there are fairly ordinary varieties of pond-scum drifting all around us. They're the main reason we can see only a couple of hundred yards, and they carry on most of the photosynthesis. There are lots of non-photosynthetic organisms—bacteria—producing carbon dioxide just as in any balanced eoology on Earth, though this place is a long way from being balanced. Sometimes the algae get so thick you can't see twenty feet, sometimes the bacteria get the upper hand. The balance keeps hunting around even when no new forms are appearing or being introduced. We probably brought a few new bacteria in with us on our suits just now; whether any of them can survive with the ammonia content of Raindrop this high I don't know, but if so the ecology will get another nudge.
     "There are lots of larger plants, too—mostly modifications of the big seaweeds of Earth's oceans. The lock behind us is overgrown with them, as you can see—you can look more closely as we go back—and a lot of them grow in contact with the outer skin, where the light is best. Quite a few are free-floating, but of course selection works fast on those. There are slow convection currents, because of Raindrop's size and rotation, which exchange water between the illuminated outer regions and the darkness inside. Free-floating weeds either adapt to long periods of darkness or die out fast. Since there is a good deal of hard radiation near the surface, there is also quite a lot of unplanned mutation over and above the regular genetailoring products we are constantly adding to the pot. And since most of the organisms here have short life spans, evolution goes on rapidly."
     "Weisanen knows all that perfectly well," replied Bresnahan. "What he seems to want is a snapshot—a report on just what the present spectrum of life forms is like."
     "I've summed it up. Anything more detailed would be wrong next week. You can look at the stuff around us—there. Those filaments which just tangled themselves on your equipment clip are a good example, and there are some bigger ones if you want there— just in reach. It would take microscopic study to show how they differ from the ones you'd have gotten a week ago or a year ago, but they're different. There will be no spectacular change unless so much growth builds up inside the surface film that the sunlight is cut down seriously. Then the selection factors will change and a radically new batch—probably of scavenger fungi—will develop and spread. It's happened before. We've gone through at least four cycles of that sort in the three years I've worked here."

     Weisanen's face showed no change in its expression of courteous interest. "That is quite all right," he said. "I should have made clear that I wanted, not a detailed biological report, but a physical description by a non-specialist of what it is like subjectively down there. I should imagine that you received an adequate impression even during your short stay. Can you give such a description?"
     Bresnahan had a good visual memory, and it was easy for him to comply. He gave a good verbal picture of the greenish, sunlit haze that had surrounded him—sunlight differing from that seen under an Earthly lake, which ripples and dances as the waves above refract it. He spoke of the silence, which had moved him to keep talking because it was the "quietest" silence he had known, and "didn't sound right."
     He was interrupted by Silbert at this point; the spaceman explained that Raindrop was not always that quiet. Even a grain-of-dust meteoroid striking the skin set up a shock wave audible throughout the great sphere; and if one were close enough to the site of collision, the hiss of water boiling out through the hole for the minute or two needed for the skin to heal could also be heard. It was rather unusual to be able to spend even the short time they had just had inside the satellite without hearing either of these sounds.
     Bresnahan nodded thanks as the other fell silent, and took up the thread of his own description once more. He closed with the only real feature he had seen to describe—the weed-grown cylinder of the water-to-space lock, hanging in greenish emptiness above the deadblack void which reached down to Raindrop's core. He was almost poetical in spots.
     The dark head nodded slowly, its gray eyes fastened on some point far beyond the metal walls. "It's fascinating," she said slowly. "Not just the way we pictured it, of course, and there will be changes anyway, but certainly worth seeing. Of course they didn't go down to the core, and wouldn't have seen much if they had. I suppose there is no life, and certainly no natural light, down there."
     "There is life," replied Silbert. "Non-photosynthetic, of course, but bacteria and larger fungi which live on organic matter swept there from the sunlit parts. I don't know whether anything is actually growing on the core, since I've never gone in that far, but free-floating varieties get carried up to my nets. A good many of those have gone to Earth, along with their descriptions, in my regular reports."
     "I know. I've read those reports very carefully, Mr. Silbert," replied Weisanen.
     "Just the same, one of our first jobs must be to survey that core," his wife said thoughtfully. "Much of what has to be done will depend on conditions down there."

     This worried him, since Silbert had become firmly attached to the notion that the Raindrop plan was an essential step to keeping the human race fed, and he had as good an appetite as anyone.

(ed note: in the story they have fusion powered torchships that makes shiping cargo up and down Terra's gravity well very inexpensive)

     He knew, as did any reasonably objective and well-read adult, how barely the advent of fusion power and gene tailoring had bypassed the first critical point in the human population explosion, by making it literally possible to use the entire surface of the planet either for living space or the production of food. As might have been expected, mankind had expanded to fill even that fairly generous limit in a few generations.
     A second critical point was now coming up, obviously enough to those willing to face the fact. Most of Earth's fourteen billion people lived on floating islands of gene-tailored vegetation scattered over the planet's seas, and the number of these islands was reaching the point where the total sunlight reaching the surface was low enough to threaten collapse of the entire food chain. Theoretically, fusion power was adequate to provide synthetic food for all; but it had been learned the hard way that man's selfishness could be raised to the violence point almost as easily by a threat to his "right" to eat natural — and tasty — food as by a threat to his "right" to reproduce without limit. As a matter of fact, the people whom Silbert regarded as more civilized tended to react more strongly to the first danger.
     Raindrop had been the proposed answer. As soon as useful, edible life forms could be tailored to live in its environment it was to be broken up into a million or so smaller units which could receive sunlight throughout their bulks, and use these as "farms."

     The first material to go into the lock consisted of half a dozen yard-wide plastic bubbles of water. Silbert noted with interest that all contained animal life, ranging from barely visible crustacea to herring-sized fish.
     "So we're starting animal life here at last," remarked the spaceman. "I thought it was a major bone of contention whether we ever would."
     "The question was settled at the first meeting of the new board," replied Weisanen. "Life forms able to live here — or presumably able to live here — have been ready for several years. Please be careful in putting those in the lock — just the odd-numbered ones first, please, first. The evens contain predators, and the others should be given a few hours to scatter before they are turned loose."

     To the mild surprise of the Weisanens and the blank astonishment of Silbert — Bresnahan knew too little to expect anything, either way — the central region of the satellite was not completely dark. The light was so faint that it would not have been noticed if they had not been turning off the sphere's lamps every few minutes, but it was quite bright enough to be seen, when they were a hundred yards or so from the core, without waiting for eyes to become dark-adapted.
     "None of your samples ever included luminous bacteria," remarked the official. "I wonder why none of them ever got close enoup to the skin for you to pick up."
     "I certainly don't know," replied Silbert. "Are you sure it's caused by bacteria?"
     "Not exactly by a long shot; it just seems the best starting guess. I'm certain it's not heat or radioactivity, and offhand I can't think of any other possibilities. Can you?"
     "No, I can't. But maybe whatever is producing the light is attached to the core — growing on it, if it's alive. So it wouldn't have reached the surface."
     The core was visible for at least two hundred yards in all directions, as the sphere spun slowly under Weisanen's control. The light definitely came from the life forms which matted its surface.
     Presumably these were fungi, since photosynthetic forms could hardly have grown in such an environment, but they were fungi which bore little resemblance to their Terrestrial ancestors. Some were ribbon-like, some feather-like, some snaky — even patches of what looked like smoothly mown lawn were visible. The greenish light was evidently not pure color, since other shades were visible; red, purple, and yellow forms stood out here and there in eye-catching contrast to grays and browns. Some forms were even green, though it seemed unlikely that this was due to chlorophyll. Practically all seemed to emit the vague light which bathed the entire scene — so uniformly that outlines would have been hard to distinguish were it not for a few specimens which were much brighter than the others. These types bore what might have been spore pods; brilliantly luminous knobs ranging from fist to grapefruit size, raised "above" the rest of the surface as much as eight or ten feet on slender stalks. These cast shadows which helped distinguish relief.
     The woman was right; weird it might be, but the scene was beautiful.
     A fair-sized stony meteoroid — really an asteroid — was used as the original core, but the soilds from the comets would be very fine dust There could be yards of mud too fine to hold any sort of anchor surrounding the solid part.

     "Aino is anchoring us now." She gestured toward the port. Her husband could now be seen through it carrying something, a harpoon, with a length of fine line attached to it. A couple of yards from the surface he poised himself and hurled the object, javelin style — or as nearly to that style as anyone can manage in water — into the mass of vegetation.
     The shaft buried itself completely. Weisanen gave a tug on the line, whose far end was attached to the sphere. He seemed satisfied and turned to look at the vehicle.

From RAINDROP by Hal Clement (1965)

      "That can't be it," objected Corrie. "The picture we get ought to show a sphere."
     "It would, in the visible part of the spectrum. We're looking at it in the thermal infra-red, remember, so we're seeing differential heat emission from different sides. Atlantis must be rotating, with the side facing away from the Sun always a bit cooler. That's why it looks lop-sided." Rob was peering with interest at the display of the asteroid. "Two kilometers across, eh? What do you think Regulo would charge to make one like that for somebody else?"
     "Price isn't the issue. He couldn't do it." Corrie saw his skeptical look. "Honestly. It's not that he wants the only one—though I suspect that he does. This one was a fluke. There will never be another like it."
     "Never is a long time. Why do you think it's one of a kind?"
     "Judge for yourself when we get there. Regulo found this about thirty-five years ago, when they were doing his first complete survey of the Belt. Nobody else realized the significance of the find, so he got the rights to it for almost nothing. Most people thought it was useless—who could use something with that composition? All the outside was water ice, more than you'd ever need for the volatiles of an orbit adjustment. There was a lump of metallic ores—very pure—sitting right in the middle, but it would be difficult to reach."
     "You mean it wouldn't pay to tunnel in and mine it? I suppose not. There are plenty of other candidates around, with more ore and less water."
     "That's what the other miners decided. But after he bought long-term rights, Regulo coated the outside with a black hi-temp plastic, started it rotating, and dropped it into a tight hyperbolic. Then he picked it up on the other side, once it was well clear of the Sun."
     Rob was busy at the calculator interface. After a few seconds he looked up and shook his head. "It wouldn't work, according to me. You'd never melt it with a single fly-by."
     "Did I say that? He had his team pick it up near Mercury and put it into a Trojan orbit with the planet. He wouldn't go near it himself, of course, not that close to the Sun. While the meltdown was going on he had a mining group confirm the first assay of the ores and do the core analysis in more detail. That became a lot easier after partial melt. It took five years to complete the change from ice to water, then they used some water in the drives to take it further out. Regulo met them near Earth and started the installation of the hydroponics systems. By that time, some of the others had begun to get an idea what he was doing."
     "And now he has it self-supporting?"
     "Completely. Regulo says that with a few months' warning Atlantis could survive if Sol went nova. He'd simply move the whole thing out to a safe range from the Sun."
     "But he's exaggerating."
     "Of course he is." Corrie laughed.
     Rob remained peering into the scope, seeking more details of the mystery asteroid ahead. Following Regulo's work, it had become a sphere of water rather less than two kilometers across. It was surrounded by a restraining membrane of tough flexible plastic, a trapping surface for solar heat. The aquasphere was pierced by twenty metal-lined shafts that served as structural braces and also provided access from the exterior of the asteroid to the central metal sphere where living quarters and laboratories were located. Other entry to the two-hundred-meter central biosphere came from the ports that connected the living quarters to the aquasphere. As they drew closer, Rob could see the silver gleam of heavy drive equipment positioned near the outer edge of each entry shaft. The whole ponderous assembly was rotating slowly about its center of mass. Small attitude jets positioned at a number of points on the surface showed how the rotation rate was controlled.
     "I thought you were just joking about getting away from a nova," said Rob. "Now, I'm not so sure. There are drives all over that thing and they look like big ones. Do you know what sort of acceleration he can get on it?"
     Corrie was busy at the communicator, tuning in for their final arrival. "Not much at all," she said. "There's plenty of power, but the limiting factor is the strength of the support shafts and the surface membrane around the aquasphere. They take the main stresses when Atlantis is accelerated. The interior is nearly all liquid water, even allowing for the support shafts and interior structures. You need monster drives for any acceleration worth speaking of, because Atlantis masses about four billion tons. That takes some shifting. Regulo usually doesn't try for more than a hundredth of a gee. He gets around, but it takes a while."
     They were creeping closer to one of the entry shafts, their angular rate matching to that of the asteroid. Close up, the surface had a dull, smooth finish, making Atlantis visible only as a black mass occulting the bright star field behind it.
     "No wonder I couldn't pick it up on the screen," said Rob. "The surface is sitting there in full sunlight but there's no radiation back-scatter at all. At least, there's not enough to see."
     "There should be hardly anything at visible wavelengths." Corrie was sitting next to him as they awaited final docking. "Morel designed it that way. The aquasphere has been made into a self-sustaining community of plants and animals. It uses all the light that it can get for photosynthesis. That's why Regulo and Morel covered it with variable albedo materials. Nothing is reflected as visible light, and all the heat goes out through the side facing away from the Sun."
     "Sounds like a violation of the Second Law of Thermodynamics to me." Rob was impatiently peering out of the side port, waiting for a glimpse of the interior. "You're telling me I won't be able to see anything at all from out here, then?"
     "That's right. Wait until we get inside, then you'll see plenty. You can even take a swim through the interior if you want to." She grinned at some secret joke. "I somehow doubt that you will. I certainly never have. I should have warned you of one other thing: be prepared for a fishy dinner. Regulo imports food when he feels like it, but he makes the point to new arrivals that he has a completely closed ecology operating in Atlantis. The human living quarters in the center are part of the overall balance, with reprocessed wastes going back into the aquasphere as nutrients. Of course, you lose a little mass when you move around the System, but Regulo replaces that occasionally from other asteroids."
     "Does Atlantis have any internal power sources? Big ones, I mean, to provide power and light."
     "There are a couple of fusion plants, and Regulo talks of adding a power kernel. Why?"
     "I was thinking of your statement that Regulo hates the Sun. With this set-up, he's independent of it. He could provide the light for photosynthesis in the aquasphere from his own power sources, and if he did that he could go as far away from the center of the System as he chose—out beyond the Halo, if he feels like it."
     "He's talked of it; but he likes to know what research is going on, in the Belt and back on Earth. If it weren't for that, I think he might take Atlantis a long way out. Maybe leave the System completely." There was a slight bump, felt through the floor of the ship. "Feel that? We're docked. We can go inside now. Regulo doesn't believe in elaborate entry procedures. Anybody that he doesn't want in Atlantis would never get this far. His computers will have checked the signature of this ship against the System ship listings when we were still a hundred thousand kilometers out."
     She stood up and led the way out of the main cabin and through the lock. The rotation rate of Atlantis was low, barely enough to give a feeling of weight. The ship had docked at the exterior surface of the asteroid, on the "equator" farthest from the axis of rotation of the sphere. A flexible umbilical led to the entry shaft. It had been attached automatically as the ship docked. As they passed into the main shaft, baffles sealed it behind them. Within thirty seconds the atmosphere in the interior was up to half a standard atmosphere, oxygen-rich and matched to that of the ship they had just left. Rob followed Corrie as she pulled herself easily along the broad, dark tunnel that led to the central metal sphere. About halfway along they halted at a second lock and removed their suits. Once they were ready to go on, Corrie led Rob to the side of the tube.
     "I think I can show you something to match your Coal Moles," she said. "You know, Morel and Regulo built a complete water-world here, and this is one of the viewing ports. You'll find the same sort of thing all over the inner sphere. Take a look through there."
     She pointed to a transparent panel about two meters across set into the side of the lock chamber. Rob went to it and looked out. It took a few seconds to become accustomed to the scale and distance of what he was seeing. Then he grunted with surprise and leaned closer to the panel.
     The water that filled the interior of Atlantis was very clear. He could see for at least a hundred meters into a green, shady interior, filled with huge and abundant plant growth. It clustered around a complex supporting grid in the form of a symmetrical series of spherical frames, like concentric shells. Between the spheres of vegetation, far away into the dim light, moving shapes were faintly visible. In rainbow colors, they turned, darted, or cruised lazily among the curtains of floating plant life. At the limit of vision, Rob fancied that he could see the phantom outline of something much bigger, a dark irregular shape outlined against the lighter green-blue background. As he watched, it drifted farther off and merged into the fronded luxuriant weeds.
     He turned back to Corrie. "That looks like a fresh-water ecology out there, but I could swear that I'm seeing forms that only live in salt water back on Earth. Is it fresh, salt, or what?"
     "It's all fresh water. There was no easy way to find a mass of salt where and when they wanted it. They discovered salt deposits later on some of the asteroids, but by that time they were committed to most of the biological forms." Corrie again began to lead the way toward the central structure. "You're quite right about the mixture of life-forms. That has been one of Morel's interests. Over the past twenty-five years he has been developing marine animals that can stand the transition from salt water to fresh. You'll see how successful he has been when you have an opportunity to examine the aquasphere. It wasn't an easy problem. Morel had to do a good deal of genetic engineering before he was satisfied with most of them."

From THE WEB BETWEEN THE WORLDS by Charles Sheffield (1979)

      "There are no planetary systems around those suns," Villimy said.
     "They're dwarf first-generation stars," Chayn said. "What these stars lack in size and brightness, they make up for in longevity. It was the larger first generation stars in the galaxy, the bigger ones, that exploded and gave birth to second and third generation suns and the heavier elements that formed the planets."
     "What is it?" Chayn asked of Villimy.
     The artifact was a sober find in a part of space where nothing could live.
     "It's a sun sail!" Villimy burst out excitedly.
     Thin cables connected thousands of square kilometers of partially collapsed, plastic film to a small cylinder with rounded ends. Inside the cabin, Chayn sensed something that had once lived. He focused on the occupant of the primitive vehicle.
     "Is it human?" Villimy asked.
     They drew close and observed in silence.
     The creature preserved in the vacuum and absolute zero of space might have died just minutes ago. Chayn could discern individual cells within the ice body of the creature. It possessed a human skeletal structure and a familiar placement of internal organs. Alive, the entity would have stood three quarters of Villimy's height, just less than half his own. But the brain in the slightly oversized skull spoke of evolutionary pressures toward a considerable intelligence.
     "It may have been drifting for millions of years," Villimy said. "It probably came from within Andromeda itself."
     "No," Chayn said. "It's traveling almost parallel to the galactic plane. It's only been drifting for a few thousand years. It had to have come from one of the nearby halo stars."
     "Chayn, how could they live out here?"
     "Pay closer attention to the engineering and technology."
     Villimy knew sun sails better than Chayn, but she was second to catch the size of the sail, its vast canopy designed to catch the weaker light of the local red dwarfs. Paying closer attention to the cabin, she sensed only film coatings of metal within a sophisticated electronic computer constructed mostly of a form of biologically derived plastic.
     "I said it myself," Villimy conceded. "There are no metallic resources out here."

     Villimy turned back toward the small planetary body orbiting the red dwarf.
     She approached closer to the bloated, angry globe of fire than would have been safe limits for a star of normal mass, within a few hundred thousand miles. But this star wasn't much larger than Jasper, the gas giant of the Rashanon system, little more than planetary size. The small moon circled the ancient, cool sun in days rather than years.
     Villimy orbited the red dwarf once, then headed for the satellite, a ruddy, barren moon no more than two thousand kilometers in diameter. She puzzled over the moon's glaring silhouette set against the bright light of Andromeda spread across the black skies. The dark side of the moon looked solid, but the sunward side glistened like a ruby mirror, swirled in a dense, pink mist.
     Villimy descended upon the airless world and learned its secret. The sunward side was an ocean churning in waves tens of meters high in the light gravity, its surface literally boiling in the vacuum. She probed the depth of the moon and found only water. The dark side of the body was a shell of ice a hundred kilometers thick. Approaching the twilight zone between the dark and the lighted side of the moon, the ice crust thinned and gave way to the shores of the ice-mist shrouded ocean.
     The satellite had no solid core. The moon was a melted snowball, a water world in the most literal sense. The life Villimy sensed lived beneath the protective cover of water. The colony of men who inhabited this strange world lived within the depths of a low-density sea of gigantic proportions.
     The scene both delighted and frightened Villimy. The satellite could not have been native to this star. It had to have been a renegade planetary body somehow thrown into intergalactic space from Andromeda and captured by this cool little red dwarf. Its orbit was eccentric, but not eccentric enough to either freeze the open waters or melt the shielded ice. Still, the boiling sea was doomed to a brief lifespan in cosmic terms. The red dwarf was ringed in a dim ice mist trailing its renegade satellite. The moon may have been larger in the past. It would be smaller in the future, and evaporate at an ever increasing rate. Lifespan? No more than a few thousand years.

     These people were starved for metal. Their electronics functioned on metallic film. She suspected that even supplying trace elements for their diet proved a challenge. She had yet to learn how they survived in a world that consisted of nothing but water, ice and vacuum beyond. What did they use for raw material?

     They called themselves the Children of the Yellow Sun in reference to their ancient, long-lost home world. Psychologically, they had never fully adapted to Hydrabyss and maintained a constant, low-level hatred of their prison of water. Their life was harsh and demanding, teetering on the razor-edge between survival and extinction. When they began to run familiar concepts together to form a mental shorthand, Children of the Yellow Sun became Chilsun. She remembered the term from her disturbing dreams during the night.
     There were two species of Chilsun, the Technologists and the Naturalists, the Techs and the Nats.
     Lorb was a the source of the dream of the yellow us, an enemy seeking their destruction, and their only source of METAL. Beyond that basic set of facts, Lorb and the Kigon starship were two factors that would remain largely unknowns.
     The reason for their still-to-be-explained relationship with Lorb, the alien enemy jealously guarding his stores of excruciatingly precious METAL.
     Hader handed her a formed piece of the black material in evidence everywhere.
     "It is called blasphar," Hader explained. "It is an organic synthetic modified to suit different needs. You will be shown how we grow it."
     "Grow it?"
     Hader nodded. He pointed to another sub in the near distance crawling with Techs wielding torches that burned with ultraviolet light. "Blasphar is easily welded, then exposed to different kinds and levels of radiation that cure it to desired specifications. The hardness can be undone. Blasphar is reused as often as necessary. Our total supply has accumulated from the beginnings of our history."
     "What source of energy do you use?" Villimy asked. "It can't be as scarce as..."
     Hader quickly interrupted her use of the word METAL. "Hydrogen fusion. In a world of water, what else but hydrogen fusion? It serves all purposes when converted into other forms of energy."
     Controlled hydrogen fusion. Generally considered to be a primitive form of energy, Villimy suspected that the Chilsun had refined it to a fine art. The only limiting resource to their civilization remained the heavier elements.
     When the craft dropped into open water, bright spotlights flashed on and gave Villimy a clear view in all directions. The water came close to being absolutely transparent. A smaller screen overhead showed a black ceiling slowly receding from them.
     Villimy expected to see an underwater city constructed of blasphar, something on the order of a space station. As Hader moved the craft swiftly up and away from the docking ports, Villimy saw a wall of irregular rock. Gaining some perspective with distance, she recognized the pitted, uneven surface.
     "It's an asteroid!" she cried out in astonishment.
     "Rocks of space provided by our ancestors," Hader said. "This is one of ten original cities built when we first colonized Hydrabyss. This city is called Yeld. It has a population of five million."
     Yeld was a city of blasphar consisting of five horizontal spokes and two vertical ones protruding from a ten-kilometer-long, irregularly-shaped rogue asteroid. Two brilliant beacons of yellow light burned on the two vertical towers protruding from the top and bottom of the city. The slender, triangular spokes were bright with thousands of windows looking out into the clear waters of Hydrabyss. Submarine entrance ports, small black pits, dotted the underside of Yeld in geometric patterns.
     Hader turned the craft away in a graceful arc and increased speed. "I will show you the Tech reefs."
     "At what depth are we?" Villimy asked.
     "Ten times the height of Yeld beneath the surface."
     That translated as about one hundred kilometers beneath the surface. In the light gravitational field, Villimy had no idea of what pressure of water the sub's hull had to resist, but if she had slowly adapted to a denser air pressure without noticing, and if she breathed an air composition designed to mask side effects, only sudden transportation to the surface and resulting decompression would give her some idea of what pressure one hundred kilometers of water represented. It would be a fatal experience, she suspected.
     Hader, for the moment, moved in a horizontal plane away from Yeld. In time, he turned off the lights. "Ahead lie the Tech reefs," he said. "We harvest food and base our cooperative genetic research stations there. The Nats have their own reefs at greater depths."
     Villimy saw a distant row of lights. As they neared, the row resolved itself into five, parallel rows. Hader arced upward to move above the lights. A rectangular landscape of misted lights spread out before her. It grew endlessly in size as they approached. Villimy gasped in astonishment as the vast landscape resolved itself into an underwater jungle of life. Forests of tall fronds rippled in a light current, their depths alive with schools of living creatures. The water turned milky in the reefs, bright in the fusion lanterns glowing tens of meters above the first of the stack of five artificial reefs, each five by twenty kilometers in size.
     "The tall plants are farmed for blasphar," Hader commented. "This reef, however, is not a kelp farm."
     Schools of fish weaved and darted as a single living entity and dived for the protection of the jagged coral far below as the sub brushed the tips of the fronds and stirred them to violent motion behind them.
     "Was all this life native to Hydrabyss when you arrived?" Villimy asked.
     "Hydrabyss is a dead world. Nothing is native to Hydrabyss, not so much as a single bacterium."
     "Where did this all come from? Did you bring it with you?"
     "We brought nothing with us. Lorb stranded us here with little more than our will to survive. All of this is the creation of our genetic engineers. Each form of life was created from human cells altered and reformed to build a self-sustaining ecology. Hydrabyss provides only water. No light, no nourishment. Man provides it all and reaps every last molecule in return. Nothing is wasted. Everything is recycled. But given light and nourishment, the reef sustains itself. Its own natural ecology and evolutionary processes now function independent of our genetic laboratories."
     "But you must have resources other than water to work with!" Villimy protested.
     "Water is power as well as the medium," Hader said, inwardly proud and amused by her reaction. "In the watery core of Hydrabyss, the Nats have built a nuclear transmutation furnace and, to a modest degree, have duplicated the element creation process that occurs naturally in the stars. Using hydrogen as the raw material, all elements can be produced in diminishing quantities, the higher radioactive elements produced only in minute amounts. Bacteria of the reefs feed upon hydrogen sulfide and all creatures along the food chain live upon that foundation. Recently, no more than a thousand years ago, we discovered ways in which plants can manufacture their own food given sufficient light."
     Photosynthesis! The Chilsun had created life from the depth and scope of their own intellect and imagination!
     "This is the natural world of the Nats," Hader stated. He spoke as a creature arose from the reef and waved a webbed hand in greeting. Hader slowed and stopped the vehicle.
     Villimy sensed the communication between the creature and Hader, but could make little of it. She stared at the being, both horrified and captivated by the beauty of what the Chilsun had done to themselves. The Nat's streamlined body stretched two meters long, its head bearing no resemblance to its human ancestry, but its black, expressionless eyes identical to Hader's. It had arms and hands and indentations along its body within which to fold them away when not in use. The legs were not simply fused into a jointed tail and fin. They did not exist. The entire lower body was redesigned to provide efficient locomotion in the watery environment. The Nat trailed luxurious and brightly colored fins and bright red gills rippled in a curve above the streamlined shoulders.
     "Hydrabyss is doomed," Hader said. "It boils away in the heat of the red sun to the vacuum of space. The day will arrive when the last molecule of water is broken into atoms of hydrogen and oxygen. Our lifeless cities and dead reefs will orbit the red sun as debris. The Naturalists seek to extend our life in Hydrabyss by coating the sea with a polymer to prevent evaporation of the waters."
     "If it can be done, it sounds like a reasonable scheme," Villimy said. The Chilsun didn't have the resources or the technology to abandon Hydrabyss en masse and seek a more hospitable environment. She could plainly see that each moment of life was dedicated to mere survival.
     Hader circled back and took the craft between two layers of the reef. Now, the profusion of life had a ceiling upon its world. With the inner levels of the reefs better insulated and better protected against nutrient loss to the open waters, even more luxurious forms of life dominated. The plants were a vivid green and the fish of every imaginable size and shape. They swam in blendings of vivid color that brightened even Hader's somber attitude toward life. She saw a faint curve of this thin lips as he gently parted the milky warm waters of the reef.
     "How many of these reefs are there?" Villimy wanted to know.
     "Each of the ten cities of the Techs have several reefs like these. The Nats have reefs that are whole worlds unto themselves at much greater depths. Our reef system is as extensive as trace element resources permit."
     "The nuclear furnace supplies trace elements?"
     Hader again glanced at her. "Some quantities. We fear converting the waters of Hydrabyss to energy and material resources will contaminate our environment. Many believe that we cannot expand the reefs beyond their present size without foreshortening our life span within Hydrabyss by an unacceptable margin."
     "There are resources to be had from one other source," Villimy said without mentioning the Kigon starship or the orgasmic word METAL.
     Hader returned to Yeld, passing again over the top of the stacked reefs on the return voyage. He skimmed over the top of the stabilized asteroid floating in the depths of Hydrabyss. Villimy looked down through a transparent dome several kilometers in diameter. An extensive luxurious garden spread out in the bubble of air below. Spoked walkways met in a central plaza sparsely scattered with pedestrians. Several small reefs were stationed just beyond the dome, giving the air-breathers within a magnificent view of the sea life of the reefs on a miniature scale.

     They descended upon a lighted landscape, a strange forest covered in light haze beneath patterns of fusion torches. When they passed beneath the lights, multiple suns hung in a sky of aquamarine.
     Villimy felt a chill of shock and a sudden ecstasy of wonder. Vast schools of fish weaved in erratic paths through tall, delicate plants bowing and rippling in slow currents. Bright coral built up over the centuries formed rugged hills and valleys, the distance hid in a bank of bluish haze. Everything was covered with color, alive and moving.
     Directly ahead, Villimy made out a building, a collection of interconnected cubes piled high, exposed faces blazing with lights from thousands of windows.
     Villimy tumbled through the water laughing and skimmed down a hundred-meter-tall stand of fronds. Schools of fish darted and churned around her, some larger and more intelligent creatures following her, aware of an alien among them. She dived to the heart of the reef, stopping just above the jumbled, disorganized landscape. Creatures like flowers covered the peaks of coral, tentacles rippling in a graceful symphony of movement as they fed upon the microscopic life hazing the landscape like a low-lying mist. In countless crags and shallow caves, unknown and unseen creatures blinked bright eyes, peering up through shadows at the intruder thrashing overhead. Tiny creatures jerked and spiraled their blind ways inches before her eyes. Behind her, the Nats followed at a distance, seeing their world from a new perspective, through the eyes and mind of a foreigner to their wonderland.

From HYDRABYSS by William Tedford (1981)

Secret Asteroid Bases

It looks just like an average asteroid. Until ... the giant camouflaged hatch opens, revealing a starship hangar bay!

I'm sure you've seen it before.

Authors who include them will impress their readers, since they just never get old. These are popular with space pirates and virtuous rebels trying to overthrow evil galactic empires.

The trouble is keeping them hidden from the authorities, since:

Having said that, they sure are popular in science fiction.

In the old video game I-WAR, the Independants are fighting a guerrilla war with the Commonwealth. The Indie's secret base is in Priesthole Asteroid, which from the outside just looks like an ordinary asteroid with an unusually deep crater.

In Leigh Brackett's RETREAT TO THE STARS the last surviving rebels against the iron tyranny of the Tri-State hide in a camouflaged asteroid base in the center of the Trojan asteroids.

Alan Nourse's RAIDERS FROM THE RINGS the exiled Spacers main base is on Asteroid Central, which is surround by a deadly maze of three thousand asteroids in carefully engineered orbits. Trying to pass the maze without knowing the navigation key is virtual suicide. Trying to penetrate the maze with missiles or kinetic energy weapons is equally pointless. So Asteroid Central is not so much secret as it is impregnable.

In the tabletop boardgame TRIPLANETARY, the asteroid Clandestine is often used by pirates or rebels. The asteroid is protected by antimatter meteor drifts which will instantly destroy any spaceship not equipped with "pseudo-magnetic grapples" (whatever they are). Same as Asteroid Central: impregnable, not secret

@spdrwhumanhead calls these "roid stations". Which is snappy, but to me has some disconcerting connotations.


(ed note: the steel boot of the Tri-State tyranny has conquered the solar system, except for tiny pockets of rebels. And the hidden rebel base in the Trojan Asteroids. But little do the rebels know that the Tri-State has managed to insert Arno the spy into the base. There he covertly sabotages the rebel plans, having drunk deep of the Tri-State Kool-Aid.)

      Arno was just entering the big common hail when the lights blinked. One-two. One-two. That meant ships landing on the icy field outside. And ships meant only one thing this time. Ralph's squadron had come back.
     He stopped beside the doorway to let the mob stream through from the dormitories, workshops and kitchen. Every thing stopped when those lights blinked, except the ceaseless hammering from the place where the rebels labored on their great ship.
     The hail was full now, silent as nearly seven thousand people can make a place. The distant clangor from the mysterious ship-building echoed loudly. Arno could follow the operations outside as clearly as though he saw them; battered ships roaring in one after the other from the dark space, landing on the frigid, airless field, being towed by ancient tugs into the camouflaged dome of the hangar.
     Arno well knew how the ships of the Tri-State, combing the Solar System for this last outpost of anarchy, had passed by the savage Trojans, over the very structures that housed their quarry.
     The strangeness of it came over Arno — how Marika could look back to the Twentieth Century as day before darkness, and he as darkness before dawn. In the Twenty-first Century the last Terran rebels had fled to Venus, and from there to Mars, and from there to the state where they were now. The all-encompassing strength of the State had followed them, driving out their heresies, their anarchies, their haphazard individualism.
     Now there was peace and system everywhere, except for the hidden plague-spots on the planets and this barren asteroid, which, through him, the Tri-State would soon destroy.

From RETREAT TO THE STARS by Leigh Brackett (1941)

(ed note: in the novel, about two hundred years prior, there were US and Soviet manned space stations loaded with city-killer nuclear bombs. The nations went to war, and ordered the stations to drop their bombs and kill all life on Terra. The station crews refused. The governments of Terra got real angry that the station crews disobeyed orders, and refused to let them return. The Spacers are the descendants of the station crews. The world government of Terra doesn't like them very much, and has re-written the history books to make the Spacers look like monsters.

Ben is a spacer, who got stuck with two Terran people: Tom and his sister Joyce Barron. As they travel in Ben's space ship, he is appalled at the lies the Barrons had been taught in history school.)

      Tom Barron's forehead creased with worry. "I don't understand," he said. "If our (Earth Space Navy) ships have actually located your (Spacer) Asteroid Central, then you must be under attack there right now. Why aren't you going there?"
     "Because we need organization first," Ben said. "Anyway, there's no way Earth ships can be attacking, even if they're on all sides of Central. That's what the Maze is there for."
     "What maze?" Tom Barron said.

     "The maze of asteroids surrounding Asteroid Central," Ben said. "When Earth started sending out pirates against us a century or so ago, our Council realized that a couple of well-placed nuclear bombs could blow Central to pieces, so they built a maze of small rocks around Central to detonate any shells that might strike home. Quite a feat of planetary engineering, hauling in mile-wide rocks and launching them in orbit around Central with Central as the primary. But now Central is surrounded by a regular swarm of satellites, moving in all directions and angles, at a dozen or more rates of speed. Any ship that tries to approach Central now without knowing the safe navigation key doesn't stand a chance in three billion of actually reaching target. It would have fifteen or twenty collisions with smaller asteroids first, and when a space ship collides with an asteroid, believe me, the asteroid wins."
     Tom thought that over. "How many asteroids are there in the Maze?"
     "About three thousand, spread out in a hundred-mile radius."
     "But how do you get through it?"
     "Well, we know the safe navigation key, for one thing. It's taped into our ships' computers. Even so it's a tricky navigational problem, since the key is never one hundred per cent right. We have to know how to handle our ships. In fact, approach to Asteroid Central is required navigation training for any Spacer who wants to operate a ship, sort of a graduation exercise. As for a ship that doesn't know the key, or one with a poor navigator, the Maze is doubly treacherous. It's a one-way road; once a ship starts in, it's certain death to try to back out again, and just as deadly to try to sit still. Once you start in, you keep going or you get smashed. It doesn't pay to get cold feet halfway through."
     Tom was still puzzled. "And you mean to say you went to all that trouble just because of the patrol ships we sent up?"
     "What else could we do if one ship could carry one bomb that would split Central into fragments if it were launched without warning?"

     Joyce, who had been following the conversation silently, joined in now. "I just can't believe that an Earth captain would fire on a city without warning," she said.
     "Mars didn't get much warning," Ben said.
     "But that was in war."
     "Do you think we were at peace before?" Ben asked. "Did you ever hear the things your pirate ships did when they came out here looking for us?"
     Joyce shook her head. "Just that they'd recovered food stores that had been stolen. Of course, before we had radiation shielding on our ships, those crews had to be interned for months, and sometimes reports were slow."
     Ben nodded grimly. "And incomplete, I'll bet. You never heard about the time Outpost 7 was bombed to rubble a few years ago, women, children, and all? They never told you about the maukis that were kidnapped? About the two-year-old baby they took back to Earth and kept in a completely black room for fourteen years without contact with another human being? Or about the children they jettisoned into space through the rocket tubes without space suits?"
     Tom and Joyce Barron just stared at him. "There never were any such stories."
     "I don't imagine there were," Ben said bitterly. "Don't you see that you've only been told what your government wanted you to know? But the truth is the truth. Your expeditionary ships would murder every Spacer child they came across; there was no limit to the torment they spread before they could be driven back. We knew we couldn't barricade all space, but maybe you can understand why we barricaded Asteroid Central with the Maze."

From RAIDERS FROM THE RINGS by Alan E. Nourse (1962)

Cyclopean Installations

Cyclopean installations always make the readers sit up and take notice. Even more so in TV or movies, since the show cannot resist displaying dizzying scenes of bottomless drops with no guard rails. Something to make acrophobics close their eyes and tremble. These scenes commonly use one-point perspective with the vanishing point set to "down".

Such installations can usually perform some cosmically powerful function:

  • The Krell Machine: allows any Krell citizen to desire something to be so, then use the power of 9,200 thermonuclear reactors to make it happen

  • Project Tic-Toc: a time machine, how cool is that?

  • Tractor Beam Controls On The Death Star: all it does is demonstrate that OSHA does not exist in the Star Wars galaxy

  • The Living Computers of Xandar: holds the still living brains of every Xandarian who has lived for the past ten million years. Contains all of Xandar's history, science, and other knowledge

  • The Great Machine: this does several things; such as controlling and widening temporal rifts, projecting the operator's mind into deep space, boost a tachyon signal over dozens of light years, and scan and project images. And it also has a defensive system capable of obliterating any warship in orbit which has less than First One technology

Spectacular Planets

When you are trying your hand at worldbuilding, please try to avoid ice planets, desert planets, swamp planets, farm planets, volcano planets, and other single-biome planets. The pejorative term for this mistake is Monocosm (term invented by Roz Kaveney). Jerry Pournelle parodied this trope with the phrase "It was raining on Mongo that morning"

Back in the 1950s nothing said "scifi" better than the ringed planet Saturn. One amusing variation is the planet Moth from The Tar Aiym Krang by Alan Dean Foster. Instead of having a full ring, it has two cresents on each side. This makes it look like the planet has wings.
The ultimate urban planet, with cities covering every square centimeter of land area (except for a few acres of Imperial Pleasure Gardens) including kilometer-high skyscrapers and kilometers of underground levels for the morlocks.

The most famous is the planet Trantor from Isaac Asimov's Foundation trilogy (but given a much more detailed description in Donald Kingsbury's pastiche Psychohistorical Crisis). Trantor is famous among those literate in science fiction, the SF illiterates are familiar with the concept mostly from the planet Coruscant from the Star Wars series of movies.
This is a famous bit of worldbuilding from the novel Mission Of Gravity by Hal Clement. The only planet in the 61 Cygni system, Mesklin's surface gravity varies from 3 gees at the equator to an outrageous 700 gees at the poles. The variation is due to the ultra-high rotation rate, it spins at twenty degrees a minute making the day some seventeen and three quarter minutes long.
This is a dumbbell-shaped double planet which are so close together that they share a common atmosphere. It is possible to fly from one planet to another with an aircraft.
These planets were the result of some worldbuilding for the ill fated "Twayne Triplet" series of science fiction novels. Uller is a planet containing silicon life while Niflheim's atmosphere contained dangerous amounts of the hideously corrosive gas fluorine.
In this allegorical story, the main planet of Alpha Virginis has a gynecomorphous mountain range called the Virgin. It is a plateau about ten thousand feet above sea level, and it looks exactly like a titanic sculpture of a nude woman in repose with lakes for eyes. (Goddess in Granite by Robert Young)
The planet has a Venus-like uninhabitable atmospheric pressure. Except for the unreasonably tall (40 kilometers) plateau Mount Lookitthat. It has habitable atmospheric pressure, a pity the surface area is only half that of California. (A Gift From Earth by Larry Niven)
Sort of the opposite of Plateau, the atmosphere is too thin for humans. A weapon called the "Wunderland Treatymaker" gouged out a long kilometer deep canyon with a size about equal to the Baja California peninsula. Air pressure at the bottom of the canyon is suitable for humans. (The Ringworld Engineers by Larry Niven)
The planet is not spherical, it is a prolate spheroid. The poles actually rise out of the amosphere in to vacuum, the atmospheric pressure at the equator is too high for human habitation, the intermediate regions are suitable for humans. (World of Ptavvs, Borderland of Sol by Larry Niven)
This is a torus (donut shape) composed of breathable gases with a jaw-dropping radius of 26,000 kilometers, about four times the radius of Terra. The smoke ring is created by a gas giant called Goldblatt's World which apparently is mostly oxygen instead of hydrogen as is usual. Goldblatt is orbiting a neutron star named Voy, just outside the Roche limit. Which means Goldblatt is constantly shedding its atmosphere to replenish the smoke ring.

There is a wide variety of life living in the free fall environment of the smoke ring, including a colony of humans. There are even aquatic creatures living in huge spherical floating ponds. (The Integral Trees, The Smoke Ring by Larry Niven)

(ed note: The protagonist was one of the astronauts on the first spaceflight to Saturn. On the lecture circuit afterwards, he is contacted by Morris Perlman, who is a tycoon owning a chain of luxury hotels. Five years later, after the protagonist's second flight to Saturn, he is contacted again by Mr. Perlman)

      Mr Perlman was waiting for me after the lecture. I didn’t recognise him, for I’d met about a million people since our last encounter. But when he gave his name, it all came back, so clearly that I realised he must have made a deep impression on my mind.
     Somehow he got me away from the crowd; though he disliked meeting people in the mass, he had an extraordinary knack of dominating any group when he found it necessary—and then clearing out before his victims knew what had happened. Though I saw him in action scores of times, I never knew exactly how he did it. At any rate, half an hour later we were having a superb dinner in an exclusive restaurant (his, of course). It was a wonderful meal, especially after the chicken and ice cream of the lecture circuit, but he made me pay for it. Metaphorically, I mean.

     Now all the facts and photos gathered by the two expeditions to Saturn were available to everyone, in hundreds of reports and books and popular articles. Mr Perlman seemed to have read all the material that wasn’t too technical; what he wanted from me was something different. Even then, I put his interest down to that of a lonely, aging man, trying to recapture a dream that had been lost in youth. I was right; but that was only a fraction of the whole picture.

     He was after something that all the reports and articles failed to give. What did it feel like, he wanted to know, to wake up in the morning and see that great, golden globe with its scudding cloud belts dominating the sky? And the rings themselves—what did they do to your mind when they were so close that they filled the heavens from end to end?
     You want a poet, I said—not an engineer. But I’ll tell you this; however long you look at Saturn, and fly in and out among its moons, you can never quite believe it. Every so often you find yourself thinking: ‘It’s all a dream—a thing like that can’t be real.’ And you go to the nearest view-port—and there it is, taking your breath away.
     You must remember that, altogether apart from our nearness, we were able to look at the rings from angles and vantage points that are quite impossible from Earth, where you always see them turned toward the sun. We could fly into their shadow, and then they would no longer gleam like silver—they would be a faint haze, a bridge of smoke across the stars.
     And most of the time we could see the shadow of Saturn lying across the full width of the rings, eclipsing them so completely that it seemed as if a great bite had been taken out of them. It worked the other way, too; on the day side of the planet, there would always be the shadow of the rings running like a dusky band parallel to the Equator and not far from it.
     Above all—though we did this only a few times—we could rise high above either pole of the planet and look down upon the whole stupendous system, so that it was spread out in plan beneath us. Then we could see that instead of the four visible from Earth, there were at least a dozen separate rings, merging one into the other.
     When we saw this, our skipper made a remark that I’ve never forgotten. ‘This,’ he said—and there wasn’t a trace of flippancy in the words—‘is where the angels have parked their halos.’

     All this, and a lot more, I told Mr Perlman in that little but oh-so-expensive restaurant just south of Central Park. When I’d finished, he seemed very pleased, though he was silent for several minutes. Then he said, about as causally as you might ask the time of the next train at your local station: ‘Which would be the best satellite for a tourist resort?

     When the words got through to me, I nearly choked on my hundred-year-old brandy. Then I said, very patiently and politely (for after all, I’d had a wonderful dinner): ‘Listen, Mr Perlman. You know as well as I do that Saturn is nearly a billion miles from Earth—more than that, in fact, when we’re on opposite sides of the sun. Someone worked out that our round-trip tickets averaged seven and a half million dollars apiece—and, believe me, there was no first-class accommodation on Endeavour I or II. Anyway, no matter how much money he had, no one could book a passage to Saturn. Only scientists and space crews will be going there, for as far ahead as anyone can imagine.’

     I could see that my words had absolutely no effect; he merely smiled, as if he knew some secret hidden from me.

     ‘What you say is true enough now,’ he answered, ‘but I’ve studied history. And I understand people—that’s my business. Let me remind you of a few facts.
     ‘Two or three centuries ago, almost all the world’s great tourist centres and beauty spots were as far away from civilisation as Saturn is today. What did—oh, Napoleon, let’s say—know about the Grand Canyon, Victoria Falls, Hawaii, Mount Everest? And look at the South Pole; it was reached for the first time when my father was a boy—but there’s been a hotel there for the whole of your lifetime.
     ‘Now it’s starting all over again. You can appreciate only the problems and difficulties, because you’re too close to them. Whatever they are, men will overcome them, as they’ve always done in the past.
     ‘For wherever there’s something strange or beautiful or novel, people will want to see it. The rings of Saturn are the greatest spectacle in the known universe: I’ve always guessed so, and now you’ve convinced me. Today it takes a fortune to reach them, and the men who go there must risk their lives. So did the first men who flew—but now there are a million passengers in the air every second of the day and night.
     ‘The same thing is going to happen in space. It won’t happen in ten years, maybe not in twenty. But twenty-five is all it took, remember, before the first commercial flights started to the moon. I don’t think it will be as long for Saturn…
     ‘I won’t be around to see it—but when it happens, I want people to remember me. So—where should we build?’

     I still thought he was crazy, but at last I was beginning to understand what made him tick. And there was no harm in humouring him, so I gave the matter careful thought.

     Mimas is too close,’ I said, ‘and so are Enceladus and Tethys.’ (I don’t mind telling you, those names were tough after all that brandy.) ‘Saturn just fills the sky, and you think it’s falling on top of you. Besides, they aren’t solid enough—they’re nothing but overgrown snowballs. Dione and Rhea are better—you get a magnificent view from both of them. But all these inner moons are so tiny; even Rhea is only eight hundred miles across, and the others are much smaller.
     ‘I don’t think there’s any real argument; it will have to be Titan. That’s a man-sized satellite—it’s a lot bigger than our moon, and very nearly as large as Mars. There’s a reasonable gravity too—about a fifth of Earth’s—so your guests won’t be floating all over the place. And it will always be a major refuelling point because of its methane atmosphere, which should be an important factor in your calculations. Every ship that goes out to Saturn will touch down there.’ (as it turns out there is no methane in Titan's atmosphere, but there is plenty of methane in Titan's lakes)
     ‘And the outer moons?’
     ‘Oh, Hyperion, Japetus, and Phoebe are much too far away. You have to look hard to see the rings at all from Phoebe! Forget about them. Stick to good old Titan. Even if the temperature is two hundred below zero, and ammonia snow isn’t the sort of stuff you’d want to ski on.’

     He listened to me very carefully, and if he thought I was making fun of his impractical, unscientific notions he gave no sign of it. We parted soon afterward—I don’t remember anything more of that dinner—and then it must have been fifteen years before we met again. He had no further use for me in all that time; but when he wanted me, he called.
     I see now what he had been waiting for; his vision had been clearer than mine. He couldn’t have guessed, of course, that the rocket would go the way of the steam engine within less than a century—but he knew something better would come along, and I think he financed Saunderson’s early work on the Paragravity Drive. But it was not until they started building fusion plants that could warm up a hundred square miles of a world as cold as Pluto that he got in contact with me again.
     He was a very old man, and dying. They told me how rich he was, and I could hardly believe it. Not until he showed me the elaborate plans and the beautiful models his experts had prepared with such remarkable lack of publicity.
     He sat in his wheel chair like a wrinkled mummy, watching my face as I studied the models and blueprints. Then he said: ‘Captain, I have a job for you…’

     So here I am. It’s just like running a spaceship, of course—many of the technical problems are identical. And by this time I’d be too old to command a ship, so I’m very grateful to Mr Perlman.
     There goes the gong. If the ladies are ready, I suggest we walk down to dinner through the Observation Lounge.
     Even after all these years, I still like to watch Saturn rising—and tonight it’s almost full.

From SATURN RISING by Arthur C. Clarke (1961)

It is theoretically possible that habitable planets exist around pulsars. Such planets must have an enormous atmosphere that convert the deadly X-rays and high energy particles of the pulsar into heat. That is stated in a scientific paper by astronomers Alessandro Patruno and Mihkel Kama, working in the Netherlands and the United Kingdom. The paper appears today in the journal Astronomy & Astrophysics.

Pulsars are known for their extreme conditions. They are neutron stars of only 10 to 30 kilometers in diameter. They have enormous magnetic fields, they accrete matter and they regularly burst out large amounts of X-rays and other energetic particles. Nevertheless, Alessandro Patruno (Leiden University and ASTRON) and Mihkel Kama (Leiden University and Cambridge University) suggest that there could be life in the vicinity of these stars.

It is the first time that astronomers try to calculate so-called habitable zones near neutron stars. The calculations show that the habitable zone around a neutron star can be as large as the distance from our Earth to our Sun. An important premise is that the planet must be a super-Earth with a mass between one and ten times of our Earth. A smaller planet will lose its atmosphere within a few thousand years. Furthermore, the atmosphere must be a million times as thick as that of the Earth. The conditions on the pulsar planet surface might resemble those of the deep sea at Earth.

The astronomers studied the pulsar PSR B1257+12 about 2300 light-years away in the constellation Virgo. They used the Chandra space telescope that is specially made to observe X-rays. Three planets orbit the pulsar. Two of them are super-Earths with a mass of four to five times our Earth. The planets orbit close enough around the pulsar to warm up. Patruno: "According to our calculations, the temperature of the planets might be suitable for the presence of liquid water on their surface. Though, we don't know yet if the two super-Earths have the right, extremely dense atmosphere."

In the future, the astronomers would love to observe the pulsar in more detail and compare it with other pulsars. The ALMA telescope of the European Southern Observatory would be able to show dust discs around neutron stars. Such disks are good predictors of planets.

Probably our Milky Way contains about 1 billion neutron stars of which about 200,000 pulsars. So far, 3000 pulsars have been studied and only 5 pulsar planets have been found. PSR B1257+12 is a much-studied pulsar. In 1992, the first exoplanets ever were discovered around this object.

Article: Neutron Star Planets: Atmospheric processes and irradiation. By: A. Patruno & M. Kama. In Astronomy & Astrophysics (free preprint)

from Netherlands Institute for Radio Astronomy (2017)

It is possible that there could be planets where terrestrial-type life could survive orbiting a neutron star, but they are likely extremely rare and transient.

The habitable zone where liquid water can persist around a star has a range ≈ 0.7√L* to 1.4√L* AU, where L* is the luminosity of the star measured in solar luminosities. The exact limits are debatable and depends somewhat on the planet's properties, but this is close enough for this answer. A typical neutron star has a low luminosity, so the habitable zone will be very close and narrow.

Neutron stars cool down very rapidly at first. A young, million-Kelvin neutron star has luminosity around 0.18 solar luminosities, but a 10 million year old neutron star is down to 0.000026, and after a billion years it will be down to a millionth of the sun. This rapid cooling means that the life zone moves inwards from around 0.3-0.6 AU for the young star to 0.003-0.007 for the 10 million year star to 0.0007-0.0014 AU for the old star.

This means that a planet orbiting inside the zone at some time will become too cold before too long unless it is very close to the star since the zone drift slows down over time. It is hence unlikely that life would naturally be able to emerge on a planet like this, since planets that are in the habitable zone early only get a few million years before they freeze. The close planets that get a long period with decent temperature also have a period of extremely hot temperature before that, when most likely all volatiles are boiled away.

(Given that such a system has experienced a supernova in its past, volatiles will have been reduced even further).

That said, I don't see a fundamental reason a close planet might not be terraformed with volatiles added from elsewhere. If we consider a planet orbiting a L*=10-6L neutron star 10-3 AU away (that is, 149,597 km from the star) it could maintain water. It would have a period of 16 minutes. There would be some relativistic corrections to the orbit, but they are minor (we are 105 Schwarzschild-radii away). It would be tidally locked (since tidal locking happens on a timescale a6), but currently there are a fair number of atmosphere models suggesting such worlds could remain stable/ Living on the shady side would also prevent the damaging UV and X-rays, which would likely strip away the atmosphere over time. The main problem is that there would not be any geodynamic dynamo to power a protective magnetic field; this is a planet that really needs it.

It is worth noting that there is a very different system around a neutron star that in principle (but likely not in practice) may be habitable, and that would be far away from an accretion disk. A quiescent accretion disk may have a luminosity about 1/3 of the sun, but when going active this increases by a factor of 1,000-10,000. So here one could imagine a planet orbiting at distance, getting powered by the accretion disk light. This will likely be too unstable to actually work over long periods and have the same hard radiation problem as the close one, but on paper (or in a suitable work of fiction) it is not impossible.

Twilight Planet

If a planet is too close to its primary star, gravitational forces tend to cause Tidal Locking. One side will always face the star in eternal day, the other will always be in darkness. The sunside will probably be too hot to live in and the darkside will be too cold.

The only habitable part of the planet will be a narrow band along the terminator, in eternal dawn or twilight depending upon how you look at it. Isaac Asimov calls them "ribbon worlds."


"What I meant, sir, is that Daled IV rotates only once per revolution. Therefore one side is constantly dark, and the other side constantly light. One might surmise that the two hemispheres have developed disparate cultures, which is a major cause of most wars."

Lt. Cdr. Data, "The Dauphin", Star Trek: The Next Generation

Tidal locking is the result of a body (a planet around a star or a moon around a planet) being close enough to its parent that the pull of gravity on the satellite is stronger on the facing side than on the other (this is actually always the case, but it's particularly noticeable if the satellite is very close to the primary or the primary's gravitational field is very intense). Over astronomical timescales the parent body's gravity will slow the satellite's rotation until one side always faces the parent and the other always faces away.

Because of this mechanism, a planet orbiting a star in this fashion will always be daytime on one side of the planet and always night on the other. Originally it was thought that the starward side would always be a blazing hot desert and the night side freezing cold. More recent computer models indicate that, assuming the planet has an atmosphere, convection currents will transfer hot air from the day side to the night side and bring cold air to the day side, alleviating the extremes somewhat.

Also known as a Twilight Planet, in reference to the perpetual twilight experienced by the narrow band between the starward side and dark-side. It is guessed that this narrow band may be capable of supporting life, and is a popular way to make a planet unique. In science fiction most of the population of a tidally locked world will inhabit this region, where the climate is fairly temperate.

Compare Single-Biome Planet. The main difference is that a tidally locked world tends to have single biomes over vast stretches of its surface, but not the whole thing. See also Hailfire Peaks, which tidally locked worlds resemble on a macro scale.

(ed note: see TV Trope page for list of examples)


      When the twenty-seven independent Trading worlds, united only by their distrust of the mother planet of the Foundation, concert an assembly among themselves, and each is big with a pride grown of its smallness, hardened by its own insularity and embittered by eternal danger — there are preliminary negotiations to be overcome of a pettiness sufficiently staggering to heartsicken the most persevering.
     It is not enough to fix in advance such details as methods of voting, type of representation — whether by world or by population. These are matters of involved political importance. It is not enough to fix matters of priority at the table, both council and dinner, those are matters of involved social importance.
     It was the place of meeting — since that was a matter of overpowering provincialism. And in the end the devious routes of diplomacy led to the world of Radole, which some commentators had suggested at the start for logical reason of central position.
     Radole was a small world — and, in military potential, perhaps the weakest of the twenty-seven. That, by the way, was another factor in the logic of the choice.

     It was a ribbon world — of which the Galaxy boasts sufficient, but among which, the inhabited variety is a rarity for the physical requirements are difficult to meet. It was a world, in other words, where the two halves face the monotonous extremes of heat and cold, while the region of possible life is the girdling ribbon of the twilight zone.
     Such a world invariably sounds uninviting to those who have not tried it, but there exist spots, strategically placed — and Radole City was located in such a one.
     It spread along the soft slopes of the foothills before the hacked-out mountains that backed it along the rim of the cold hemisphere and held off the frightful ice. The warm, dry air of the sun-half spilled over, and from the mountains was piped the water — and between the two, Radole City became a continuous garden, swimming in the eternal morning of an eternal June.
     Each house nestled among its flower garden, open to the fangless elements. Each garden was a horticultural forcing ground, where luxury plants grew in fantastic patterns for the sake of the foreign exchange they brought — until Radole had almost become a producing world, rather than a typical Trading world.
     So, in its way, Radole City was a little point of softness and luxury on a horrible planet — a tiny scrap of Eden — and that, too, was a factor in the logic of the choice.

From FOUNDATION AND EMPIRE by Isaac Asimov (1945)

We (virtually) stood on a plain of black, rugged basalt at the edge of a cliff above a seething ocean. The city of Salvation, the Neoessenist capital, seemed to grow from the rocks a kilometer in the distance, a collection of white domes and truncated pyramids emerging from a cliff face beyond the sprawl of a small spaceport. The red dwarf sun hung low in a deep green sky, partially obscured by the scudding purple cloud wrack. Even at this distance from the star—just twenty-two million kilometers—you could look straight into its ruddy face without discomfort and count the mottled black-on-red splotches of its starspots. Sky color depended on the angle of the incoming sunlight, and on this world it could be anything from sunset red to a deeply contrasting green.

A furious wind was blowing, so powerful that had I been there physically, it would have been difficult to stand. I was aware of it in sim because the viewpoint camera was trembling slightly as spray from the ocean whipped past, and the vegetation nearby—short, scrubby growths with feathery black leaves and rubbery stalks—was whipping back and forth, and, during the strongest gusts, lay flat against the ground.

Bloodworld, you see, is tidally locked with its primary, always turning the same side to face the sun, one hemisphere forever in daylight, the other in darkness. The colony had been established here in the so-called twilight band between day and night; as it circled its star, Bloodworld rocked back and forth, a nodding movement called libration, which resulted in the sun appearing to rise above the horizon for a few days, then setting, the landscape eternally balanced between fire and ice. The planet’s atmosphere—one and half times denser than that at Earth’s surface—expanded rapidly in the middle of the dayside, creating powerful winds blowing from day to night, winds that served to even out the planet’s temperature extremes and keep all of the water and carbon dioxide from freezing out permanently over the nightside.

The landscape receded suddenly, the surface of the planet dropping away to merge with a planetary graphic, a computer-generated map of Bloodworld showing terrain features crossed by lines of longitude and latitude. I was looking down on the planet’s nightside, at a vast splash of glaciers radiating from the midnight area, amid ocean, bare rock, and ice-sheathed mountains.

“At this point in the planning process,” Carter continued, as a green, curving line arced down across the glacier, approaching the planet’s surface close to the horizon, “we are assuming a landing by D-Mist (a stealth landing craft) on the planet’s nightside, with a combat skimmer approach to the twilight band.”

The planet graphic rotated to show the narrow band circling the world from pole to pole, the narrow strip of approximately temperate surface between the heat of the daytime desert and the frozen ice of the night. Several cities were located there, balanced between light and the darkness.

From BLOODSTAR by William Keith (as Ian Douglas pseudonym) (2012)

Killer Planet

Ah, the good old Planet Of No Return! Where the environment is slow death, the geology is full of earthquakes and volcanoes, the plants are poisonous and carnivorous, and there are more animals that can kill you than Australia.

But do try to have a bit of internal self consistency when you create your death world. In the old Lost In Space episode "A Day at the Zoo" they become trapped on a planet along with a native teenage alien named Oggo. Another alien notes that the life expectancy on the planet is about fifteen minutes, which leaves the puzzle of how the alien teenager got so old.

People who call a Killer Planet "Home" tend to be called "The Most Deadly Warriors In The Entire Galaxy." If you can survive there, you can survive anywhere. Naturally such warriors are in high demand and get top dollar.

Examples include:

DEATHWORLD by Harry Harrison
     The heavy-gravity constant-earthquake tsunami-prone planet Pyrrus is home to plants and animals that evolved telepatic communication and cooperation in order to survive. The high background radiation ensures that it does all its evolution very quickly. Basically the entire ecosystem is a hive mind.
     Regrettibly, the first human colonists inadvertenly made the ecosystem very very angry.
     Since then it has been an arms race between the ecosystem evolving new and more deadly flora and fauna and the colonists training themselves and future generations how to be more efficient killing machines out of simple survival. Which means they are super-soldiers.
DUNE Frank Herbert
     The planet Salusa Secundus is so horrible it became the Corrino prison planet. It became the planet where the "worst riff-raff in the galaxy are sent."
     Naturally it bred super-soldiers. The most deadly are recruited into the dreaded Imperial Sardaukar.
     Unfortunatly for them the planet Dune is even more deadly. A total desert planet with practically no water and infested with giant sand worms makes Salusa Secundus look like a resort island. The native Fremen are so ferocious that a Fremen child is more than a match for a Sardaukar.
GALACTIC PATROL by E. E. "Doc" Smith
     Like everything else Doc Smith did, he not only invented the science fictional concept, but he simultaneously turned it up to 11.
     The planet Trenco takes the cake.
     The atmosphere is not air, the oceans are not water. The seas are of a chemical of low latent heat of vaporization, with a boiling-point such that during the daytime it is a vapor and at night a liquid. The air has feeble stopping power, so the nights are icy cold and the days are blazing hot. Which means during the 13 hour night it doesn't rain a few inches of precipitation, it rains forty-seven feet and five inches every night.
     There is lightning as well. Not a bolt or to, it is continuous. So much that it warps space. If you shoot a blaster at somebody it is possible for the beam to be bent such that it strikes you in the back.
     Did I mention that the wind blows at 800 miles per hour?
     And then there are the animals and plants. Who constantly eat each other while they are themselves being eaten.
     The protagonist is with an alien called an "Ezwal" in a space ship. The ship is shot down and crash lands on a planet. An Ezwal has a mass of almost three metric tons, six limbs each with claws that can slap the head off an elephant, is smarter than Einstein, and telepathic to boot.
     The planet is Eristan II, which is a killer planet. The protagonists knows all about it, the Ezwal had never heard of it.
     The protagonist offers to team up with the Ezwal, saying that together we have a chance of survival.
     The Ezwal looks down its nose at the protagonist, says "What do you mean we, white man? How tough could this planet possibly be?", and trots into the forest.
     About an hour later the Ezwal come galloping back to the protagonist and pleads for help...
MIDWORLD by Alan Dean Foster
The entire planet is covered by a rain forest. However the trees are about 0.75 kilometers tall. The base of the trees are swamps in mindless darkness infested by monsters that can eat an elephant like an after dinner mint. The tree tops are infested by eternally hungry pteranodon-like flying reptiles. The only part of the world that is not swift death is the middle area between the swamp and the sky. And that is only relative. There are deadly plants like the grenade fruit, which kills you with an explosion that simultaneously sends seeds deep into your fresh corpse to grow. And the false cubble-vines, which look just like the roadway type vines but which will literally bite your foot off. But the worse is the army ants, devouring all in their path. Except these ants are the size of a hippo.

"We've run into scorpions the size of battle tanks, three men died from Eyerot last week, I've sweated enough to fill a lake, my boots just got sucked into a sink-swamp and the trees are so thick in places, you can't squeeze between them. Emperor help me, I love this place! It's just like home!"

Captain Rock of Catachan, Warhammer 40,000

A Death World is a highly dangerous place, where simply going there is considered taking your life into your own hands. It could be from hazardous environmental conditions, such as an acidic swamp or poisonous fog, or from powerful native predators (Here there be Dragons, or worse, something that eats them), dangerous flora, or even all of the above. It's like the entire place is deliberately hostile to human life. (Of course, if it's also a Genius Loci, it just might be!)

Very few people would ever choose to live there, but since anyone who does is almost always a badass, expect any populated Death World to be a World of Badass by default. Sometimes, The Mentor may hide out here. Alternately, it may be Mordor, and/or home for an exceptionally tough and ferocious race. Some actually take advantage of this as a way of training their Super Soldiers on a planetary scale. Sure, half of the population might not survive through adolescence, but those who do should make good soldiers. Sometimes they are genetically engineered. Those who live on such a world may be an example of Had To Be Sharp.

In real life, every planet outside Earth that we know of to a reasonable degree, is dangerous, because we have yet to verify that any other planet out there can support human life. In fiction, Death worlds generally have relatively breathable atmospheres (for native life, at least), have compelling reasons for characters to get out and walk around, and have varieties of dangerous flora and fauna. A planet that cannot host life for any amount of time is just "uninhabitable", not this.

For more details, the various Videogame Settings actually do a decent job of describing the various kinds of dangers you might find in different ecosystems, as a result of Everything Trying to Kill You. The Dark World is often a magical variant. Don't be too surprised if there are More Predators Than Prey.

The Trope Namer is Harry Harrison's novel from 1960, Deathworld, in which the entire flora and fauna of a planet treat the human colonizers as enemies and do their best to kill them.

Compare to Gaia's Vengeance where a world can become like this as a response to some threat. For examples of entire Death Universes, see Crapsack World.

Truth in Television: There are plenty of environments here on our own planet that can and will kill those who fail to prepare for them or take the appropriate precautions around their hazards. Even the most fantastic fictional examples are often extrapolations of dangers present here on Earth — and that's before we get into the fact that we still haven't found any worlds outside our own that are particularly inviting for human life.

Not to be confused with a Place Worse Than Death, which refers to Real Life locations with bad publicity.

(ed note: see TV Trope page for list of examples)


(ed note: Our heroes, traveling in the spaceship Skylark, land on a jungle planet. When the monsters appear, Seaton only has a clip of x-plosive atomic bullets in his gun. If one goes off too near the spaceship, the blast will wreck it.)

As they reached the broken projections, Margaret glanced back over her shoulder and screamed. The others saw that her face was white and her eyes wide with horror, and Seaton instinctively drew his pistol as he whirled about, only to check his finger on the trigger and lower his hand.

"Nothing but X-plosive bullets," he growled in disgust, and in helpless silence the four watched an unspeakably hideous monster slowly appear from behind the Skylark. Its four huge, squat legs supported a body at least a hundred feet long, pursy and ungainly; at the extremity of a long and sinuous neck a comparatively small head seemed composed entirely of a cavernous mouth armed with row upon row of carnivorous teeth. Dorothy gasped with terror and both girls shrank closer to the two men, who maintained a baffled silence as the huge beast passed his revolting head along the hull of the vessel.

"I dare not shoot, Martin," Seaton whispered, "it would wreck the bus. Have you got any solid bullets?"

"No. We must hide behind these small ledges until it goes away," answered Crane, his eyes upon Margaret's colorless face. "You two hide behind that one, we will take this one."

"Oh, well, it's nothing to worry about, anyway. We can kill him as soon as he gets far enough away from the boat," said Seaton as, with Dorothy clinging to him, he dropped behind one of the ledges. Margaret, her staring eyes fixed upon the monster, remained standing until Crane touched her gently and drew her down beside him.

There came the crack of a rifle from the Skylark. There was an awful roar from the dinosaur, which was quickly silenced by a stream of machine-gun bullets.

"Blackie's on the job—let's go!" cried Seaton, and they raced up the slope. Making a detour to avoid the writhing and mutilated mass they plunged through the opening door. DuQuesne shut it behind them and in overwhelming relief, the adventurers huddled together as from the wilderness without there arose an appalling tumult.

The scene, so quiet a few moments before, was instantly changed. The trees, the swamp, and the air seemed filled with monsters so hideous as to stagger the imagination. Winged lizards of prodigious size hurtled through the air, plunging to death against the armored hull. Indescribable flying monsters, with feathers like birds, but with the fangs of tigers, attacked viciously. Dorothy screamed and started back as a scorpion-like thing with a body ten feet in length leaped at the window in front of her, its terrible sting spraying the glass with venom. As it fell to the ground, a huge spider—if an eight-legged creature with spines instead of hair, many-faceted eyes, and a bloated, globular body weighing hundreds of pounds, may be called a spider—leaped upon it and, mighty mandibles against poisonous sting, the furious battle raged. Several twelve-foot cockroaches climbed nimbly across the fallen timber of the morass and began feeding voraciously upon the body of the dead dinosaur, only to be driven away by another animal, which all three men recognized instantly as that king of all prehistoric creatures, the saber-toothed tiger. This newcomer, a tawny beast towering fifteen feet high at the shoulder, had a mouth disproportionate even to his great size—a mouth armed with four great tiger-teeth more than three feet in length. He had barely begun his meal, however, when he was challenged by another nightmare, a something apparently half-way between a dinosaur and a crocodile. At the first note the tiger charged. Clawing, striking, rending each other with their terrible teeth, a veritable avalanche of bloodthirsty rage, the combatants stormed up and down the little island. But the fighters were rudely interrupted, and the earthly visitors discovered that in this primitive world it was not only animal life that was dangerous.

The great tree standing on the farther edge of the island suddenly bent over, lashing out like a snake and grasping both. It transfixed them with the terrible thorns, which were now seen to be armed with needlepoints and to possess barbs like fish-hooks. It ripped at them with the long branches, which were veritable spears. The broad leaves, armed with revolting sucking disks, closed about the two animals, while the long, slender twigs, each of which was now seen to have an eye at its extremity, waved about, watching each movement of the captives from a safe distance.

If the struggle between the two animals had been awful, this was Titanic. The air was torn by the roars of the reptile, the screams of the great cat, and the shrieks of the tree. The very ground rocked with the ferocity of the conflict. There could be but one result—soon the tree, having absorbed the two gladiators, resumed its upright position in all its beauty.

From THE SKYLARK OF SPACE by E. E. "Doc" Smith (1920)

It looked sinister and dark: no sun, no moon illumined this celestial body; only a bloody gleam, not unlike the Northern Light, oozed down out of the atmosphere, apparently proceeding from phosphorescent matter or bacteria in the air.

For all this illumination, little could be seen; but what they did see left a revolting impression.

The land seemed to be fairly level, mostly swampy in character.

At certain spots, luminous fumes or vapor rose from the swamps, which shed a cadaverous, sulphuric light; in between, bluish and greenish tongues of flame shot up, so that the immediate surroundings were lit by a dull gleam which was more gruesome than the most infernal torches would have been, in a world of horrors.

Yes, a world of horrors! What kind of trees and plants were these! All of them seemed alive and at the same time repulsive: grasses which wound, twisted, and squirmed about on the ground in convulsive jerks like loathsome vermin, as if striving in vain to be free from the putrid soil in which they were rooted! Many-limbed trees, whose bleak, leafless branches curled like monster serpents or octopi, in constant motion, stretching out and drawing back, forming waves, arches, rings, and knots, as if the living branches of every tree were engaged in murderous combat.

And down below, the swamps teemed with ghastly creatures: whitish maggots, larger than elephants, bared their teeth in snarls; monster spiders, whose fat, spherical bodies were covered above, below, and at the sides with long, thin, hairy legs, so that they could revolve around themselves and always crawl with a number of feet while the others quivered in the air; greenish toads as large as buffaloes, with hideous eyes popping out of their wormlike heads; thin-legged mosquitoes as tall as giraffes, which sucked the life out of other animals with their long, transparent fangs or else were bitten and crushed to death by them.

Everything crawled and fought against everything else; not only animal against animal, but also plant and animal, were engaged in incessant, deadly warfare.

There a gigantic worm with crocodile’s jaws bit off the branch of a tree and the branch twitched and jerked and squirmed convulsively on the ground, while a thick, greenish-black juice gushed from the stump, distorted as if in the ghastliest pain.

Here was one of the monster beasts with countless arms, seized by a tree and seeking in vain with desperate contortions to free itself from the fatal embrace: it was squeezed, strangled, and crushed into a shapeless mass.

And then slender vermin shot up out of the morass, sailed through the air, and bored through the body of a no less repulsive beast, finally to vanish completely into its bulk, there to commence on its entrails its ghastly work of destruction.

It was blood-curdling to watch such a monster-beast, itself gruesome in appearance, leaping about in terrific pain, to see it writhe madly and finally collapse in the throes of death, while its shapelessly swollen bulk suddenly burst open and revealed a mass of serpentine vermin which had devoured its still living body from within.

Then the livid flames shot up again through these teeming masses, singeing and devouring the bodies which vainly sought to escape: even these infernal fire-serpents seemed to be alive and to pursue their victims with bloodthirstiness.

Heliastra was deathly pale and filled with horror: “Is this what the Earth looks like?” she asked uneasily.

“No,” Hank consoled her. “This ghastly spectacle fills us also with a horror we have never known before!”

“Yes,” the Professor reassured her. “Even scientific investigation revolts here and turns away in disgust. This is a realm of darkness in the fullest sense of the word, and I propose to give it the name ‘Sheol.’”

“It is enough,” said Flitmore. “Rather into the eternal night of solitary space than watch such a spectacle any longer !” And he switched the centrifugal power on at full force.

From WUNDERWELTEN (DISTANT WORLDS) by Friedrich Mader (1911)

Judged by any earthly standards the planet Trenco was—and is—a peculiar one indeed. Its atmosphere, which is not air, and its liquid, which is not water, are its two outstanding peculiarities and the sources of most of its others. Almost half of that atmosphere and by far the greater part of the liquid phase of the planet is a substance of extremely low latent heat of vaporization, with a boiling point such that during the daytime it is a vapor and at night a liquid. To make matters worse, the other constituents of Trenco’s gaseous envelope are of very feeble blanketing power, low specific heat, and of high permeability, so that its days are intensely hot and its nights are bitterly cold.

At night, therefore, it rains. Words are entirely inadequate to describe to anyone who has never been there just how it does rain during Trenco’s nights. Upon Earth one inch of rainfall in an hour is a terrific downpour. Upon Trenco that amount of precipitation would scarcely be considered a mist, for along the equatorial belt, in less than thirteen Tellurian hours, it rains exactly forty-seven feet and five inches every night—no more no less, each and every night of every year.

Also there is lightning. Not in Terra’s occasional flashes, but in one continuous, blinding glare which makes night as we know it unknown there; in nerve-wracking, battering, sense-destroying discharges which make ether and sub-ether alike impenetrable to any ray or signal short of a full driven power beam. The days are practically as bad. The lightning is not violent then, but the bombardment of Trenco’s monstrous sun, through that outlandishly peculiar atmosphere, produces almost the same effect.

Because of the difference in pressure set up by the enormous precipitation always and everywhere upon Trenco there is wind—and what a wind! Except at the very poles, where it is too cold for even Trenconian life to exist, there is hardly a spot in which or a time at which an Earthly gale would not be considered a dead calm, and along the equator, at every sunrise and at every sunset, the wind blows from the day side to the night side at the rate of well over eight hundred miles an hour!

Through countless thousands of years wind and wave have planed and scoured the planet Trenco to a geometrically perfect oblate spheroid. It has no elevations and no depressions. Nothing fixed in an Earthly sense grows or exists upon its surface, no structure has ever been built there able to stay in one place through one whole day of the cataclysmic meteorological phenomena which constitute the natural Trenconian environment.

There live upon Trenco two types of vegetation, each type having innumerable sub-divisions. One type sprouts in the mud of morning, flourishes flatly, by dint of deeply sent and powerful roots, during the wind and the heat of the day, comes to full fruit in later afternoon, and at sunset dies and is swept away by the flood. The other type is freefloating. Some of its genera are remotely like footballs, others resemble tumbleweeds, still others thistledown, hundreds of others have not their remotest counterparts upon Earth. Essentially, however, they are alike in habits of life. They can sink in the “water” of Trenco, then can burrow in its mud, from which they derive part of their sustenance, they can emerge therefrom into the sunlight, they can, undamaged float in or roll along before the ever-present Trenconian wind, and they can enwrap, entangle, or otherwise seize and hold anything with which they come in contact which by any chance may prove edible.

Animal life, too, while abundant and diverse, is characterized by three qualities. From lowest to very highest it is amphibious, it is streamlined, and it is omnivorous. Life upon Trenco is hard, and any form of life to evolve there must of stern necessity be willing yes, even anxious, to eat literally anything available. And for that reason all surviving forms of life, vegetable and animal, have a voracity and a fecundity almost unknown anywhere else in the galaxy.

Thionite, the noxious drug referred to earlier in this narrative, is the sole reason for Trenco’s galactic importance. As chlorophyll is to Earthly vegetation, so is thionite to that of Trenco. Trenco is the only planet thus far known upon which this substance occurs, nor have our scientists even yet been able either to analyze or to synthesize it.

Thionite is capable of affecting only the races who breathe oxygen and possess warm blood, red with hemoglobin. However, the planets peopled by such races are legion, and very shortly after the drug’s discovery hordes of addicts smugglers, peddlers, and out-and-out pirates were rushing toward the new Bonanza. Thousands of these adventurers died, either from each other’s ray-guns or under an avalanche of hungry Trenconian life; but, thionite being what it is, thousands more kept coming. Also came the Patrol, to curb the evil traffic at its source by beaming down ruthlessly any being attempting to gather any Trenconian vegetation.

Thus between the Patrol and the drug syndicate there rages a bitterly continuous battle to the death. Arrayed against both factions is the massed life of the noisome planet, omnivorous as it is, eternally ravenous, and of an individual power and ferocity and a collective aggregate of numbers by no means to be despised. And eternally raging against all these contending parties are the wind, the lightning, the rain, the flood, and the hellish vibratory output of Trenco’ s enormous, malignant, blue-white sun.

Kinnison obeyed; and, released from all duty, the visitors stared in fascinated incredulity into the visiplate. For that at which they stared was and must forever remain impossible of duplication upon Earth, and only in imagination can it be even faintly pictured. Imagine all the fantastic and monstrous creatures of a delirium-tremens vision incarnate and actual. Imagine them being hurled through the air, borne by a dust-laden gale more severe than any the great American dust-bowl or Africa’s Sahara Desert ever endured. Imagine this scene as being viewed, not in an ordinary, solid distorting mirror, but in one whose falsely reflecting contours were changing constantly, with no logical or intelligible rhythm, into new and ever more grotesque warps. If imagination has been equal to the task, the resultant is what the visitors tried to see.

As the end of the third hour neared, Kinnison watched with a spy-ray—there were no windows in Trenco spaceport—the leeward groundway of the structure. In spite of the weird antics of Trenco’s sun—gyrating, jumping, appearing and disappearing—he knew that it was going down. Soon he saw the ground-car coming in, scuttling crabwise, nose into the wind but actually moving backward and sidewise. Although the “seeing” was very poor, at this close range the distortion was minimized and he could see that, like its parent craft, the ground-car was a blister. Its edges actually touched the ground all around, sloping upward and over the top in such a smooth reverse curve that the harder the wind blew the more firmly was the vehicle pressed downward.

The ground-flap came up just enough to clear the car’s top and the tiny craft crept up. But before the landing bars could seize her the ground-car struck an eddy from the flap—an eddy in a medium which, although gaseous, was at that velocity practically solid. Earth blasted away in torrents from the leading edge, the car leaped bodily into the air and was flung away, end over end. But Tregonsee, with consummate craftsmanship, forced her flat again, and again she crawled up toward the flap. This time the landing-bars took hold and, although the little vessel fluttered like a leaf in a gale, she was drawn inside the port and the flap went down behind her. She was then sprayed, and Tregonsee came out.

     “Why the spray?” thought Kinnison, as the Rigellian entered his control-room.
     “Trencos. Much of the life of this planet starts from almost imperceptible spores. It develops rapidly, attains considerable size, and consumes anything organic it touches. This port was depopulated time after time before the lethal spray was developed. Now turn your spy-ray again to the lee of the port.”

During the few minutes that had elapsed the wind had increased in fury to such an extent that the very ground was boiling away from the trailing edge in the tumultuous eddy formed there, ultra-streamlined though the space-port was. And that eddy, far surpassing in violence any storm known to Earth, was to the denizens of Trenco a miraculously appearing quiet spot in which they could stop and rest, eat and be eaten.

A globular monstrosity had thrust pseudopodia deep into the boiling dirt. Other limbs now shot out, grasping a tumble-weed-like growth. The latter fought back viciously, but could make no impression upon the rubbery integument of the former. Then a smaller creature, slipping down the polished curve of the shield, was enmeshed by the tumbleweed. There ensued the amazing spectacle of one-half of the tumbleweed devouring the newcomer, even while its other half was being devoured by the globe!

     “Now look out farther… still farther,” directed Tregonsee.
     “I can’t. Things take on impossible motions and become so distorted as to be unrecognizable.”
     “Exactly. If you saw a zwilnik out there, where would you shoot?”
     “At him, I suppose—why?”
     “Because if you shot at where you think you see him, not only would you miss him, but the beam might very well swing around and enter your own back. Many men have been killed by their own weapons in precisely that fashion. Since we know, not only what the object is, but exactly where it is, we can correct our lines of aim for the then existing values of distortion. This is of course the reason why we Rigellians and other races possessing the sense of perception are the only ones who can efficiently police this planet.”
     “Reason enough, I’d say, from what I’ve seen,” and silence fell.

For minutes the two Lensmen watched, while creatures of a hundred kinds streamed into the lee of the space-port and killed and ate each other. Finally something came crawling up wind, against that unimaginable gale, a flatly streamlined creature resembling somewhat a turtle, but shaped as was the ground-car. Thrusting down long, hooked flippers into the dirt it inched along, paying no attention. to the scores of lesser creatures who hurled themselves upon its armored back, until it was close beside the largest football-shaped creature in the eddy. Then, lightning-like, it drove a needle-sharp organ at least eight inches into the leathery mass of its victim. Struggling convulsively, the stricken thing lifted the turtle a fraction of an inch—and both were hurled instantly out of sight, the living ball still eating a luscious bit of prey despite the fact that it was impaled upon the poniard of the turtle and was certainly doomed.

The rain came—forty-four inches per hour of rain—and the incessant lightning. The dirt became first mud, then muddy water being driven in fiercely flying gouts and masses. Now, in the lee of the space-port, the outlandish denizens of Trenco were burrowing down into the mud—still eating each other and anything else that came within reach.

The water grew deeper and deeper, its upper surface now whipped into frantic sheets of spray. The structure was now afloat, and Kinnison saw with astonishment that, small as was the exposed surface and flatly curved, yet it was pulling through the water at frightful speed the wide-spreading steel sea-anchors which were holding its head to the gale.

     “With no reference points how do you know where you’re going?” he demanded.
     “We neither know nor care,” responded Tregonsee, with a mental shrug. “We are like the natives in that. Since one spot is like every other spot, why choose between them?”
     “What a world—what a world! However, I am beginning to understand why thionite is so expensive,” and, overwhelmed by the ever-increasing fury raging outside, Kinnison sought his bunk.

Morning came, a reversal of the previous evening. The liquid evaporated, the mud dried, the flat-growing vegetation sprang up with shocking speed, the animals emerged and again ate and were eaten.

From GALACTIC PATROL by E. E. "Doc" Smith (1937)
      “It has meaning enough,” Kerk told him. “But only on one planet in the universe. Just how much do you know about Pyrrus?”
     “Absolutely nothing.”
     For a moment Kerk sat wrapped in memory, scowling distantly. Then he went on.
     “Mankind doesn’t belong on Pyrrus—yet has been there for almost three hundred years now. The age expectancy of my people is sixteen years. Of course most adults live beyond that, but the high child mortality brings the average down.
     “It is everything that a humanoid world should not be. The gravity is nearly twice earth normal. The temperature can vary daily from arctic to tropic. The climate—well you have to experience it to believe it. Like nothing you’ve seen anywhere else in the galaxy.”
     “I’m frightened,” Jason said dryly. ‘What do you have, methane or chlorine reactions? I’ve been down on planets like that—”
     Kerk slammed his hand down hard on the table. The dishes bounced and the tablelegs creaked. “Laboratory reactions!” he growled. “They look great on a bench—but what happens when you have a world filled with those compounds? In an eye-wink of galactic time all the violence is locked up in nice, stable compounds. The atmosphere may be poisonous for an oxygen breather, but taken by itself it’s as harmless as weak beer.
     “There is only one setup that is pure poison as a planetary atmosphere. Plenty of H2O, the most universal solvent you can find, plus free oxygen to work on—”

     “Water and oxygen!” Jason broke in. “You mean Earth—or a planet like Cassylia here? That’s preposterous.”
     “Not at all. Because you were born in this kind of environment, you accept it as right and natural. You take it for granted that metals corrode, coastlines change, and storms interfere with communication. These are normal occurrences on oxygen-water worlds. On Pyrrus these conditions are carried to the nth degree.
     “The planet has an axial tilt of almost 42 degrees, so there is a tremendous range of temperature from season to season. This is one of the prime causes of a constantly changing icecap. The weather generated by this is spectacular to say the least.”

     “If that’s all,” Jason said, “I don’t see why…”
     “That’s not all—it’s barely the beginning. The open seas perform the dual destructive function of supplying water vapor to keep the weather going, and building up gigantic tides. Pyrrus’ two satellites, Samas and Bessos, combine at times to pull the oceans up into thirty meter tides. And until you’ve seen one of these tides lap over into an active volcano you’ve seen nothing.
     “Heavy elements are what brought us to Pyrrus—and these same elements keep the planet at a volcanic boil. There have been at least thirteen supernovas in the immediate stellar neighborhood. Heavy elements can be found on most of their planets of course—as well as completely unbreathable atmospheres. Long-term mining and exploitation can’t be done by anything but a self-sustaining colony. Which meant Pyrrus, where the radioactive elements are locked in the planetary core, surrounded by a shell of lighter ones. While this allows for the atmosphere men need, it also provides unceasing vulcanic activity as the molten plasma forces its way to the surface.”
     For the first time, Jason was silent. Trying to imagine what life could be like on a planet constantly at war with itself.

     “I’ve saved the best for last,” Kerk said with grim humor. “Now that you have an idea of what the environment is like—think of the kind of life forms that would populate it. I doubt if there is one offworld specie that would live a minute. Plants and animals on Pyrrus are tough. They fight the world and they fight each other. Hundreds of thousands of years of genetic weeding-out have produced things that would give even an electronic brain nightmares. Armor-plated, poisonous, claw-tipped and fanged-mouthed. That describes everything that walks, flaps or just sits and grows. Ever see a plant with teeth—that bite? I don’t think you want to. You’d have to be on Pyrrus and that means you would be dead within seconds of leaving the ship. Even I’ll have to take a refresher course before I’ll be able to go outside the landing buildings. The unending war for survival keeps the life forms competing and changing. Death is simple, but the ways of dealing it too numerous to list.”
     “I suppose there is no logical reason why we should stay and fight this endless war. Except that Pyrrus is our home.” The last piece of gravy-soaked bread vanished and he waved the empty fork at Jason. “Be happy you’re an offworlder and will never have to see it.”

     They were all there ahead of him, two of the men rolling transparent cylinders from a nearby room. From their obvious weight and the way they clanged when they bumped, Jason knew they were made of transparent metal. He couldn’t conceive any possible use for them. Empty cylinders a meter in diameter, longer than a man. One end solid, the other hinged and sealed. It wasn’t until Kerk spun the sealing wheel and opened one of them that their use became apparent.
     “Get in,” Kerk said. “When you’re locked inside, you’ll be carried out of the ship.”
     “Thank you, no,” Jason told him. “I have no particular desire to make a spectacular landing on your planet sealed up like a packaged sausage.”
     “Don’t be a fool,” was Kerk’s snapped answer. “We’re all going out in these tubes. We’ve been away too long to risk the surface without reorientation.”

     Jason did feel a little foolish as he saw the others getting into tubes. He picked the nearest one, slid into it feet first, and pulled the lid dosed. When he tightened the wheel in the center, it squeezed down against a flexible seal. Within a minute the CO2 content in the closed cylinder went up and an air regenerator at the bottom hummed into life.
     Kerk was the last one in. He checked the seals on all the other tubes first, then jabbed the airlock override release. As it started cycling, he quickly sealed himself in the remaining cylinder. Both inner and outer locks ground slowly open and dim light filtered in through sheets of falling rain.
     For Jason, the whole thing seemed an anticlimax. All this preparation for absolutely nothing. Long, impatient minutes passed before a lift truck appeared driven by a Pyrran. He loaded the cylinders onto his truck like so much dead cargo. Jason had the misfortune to be buried at the bottom of the pile so could see absolutely nothing when they drove outside.

     It wasn’t until the man-carrying cylinders had been dumped in a metal-walled room, that Jason saw his first native Pyrran life.
     The lift truck driver was swinging a thick outer door shut when something flew in through the entrance and struck against the far wall. Jason’s eye was caught by the motion; he looked to see what it was when it dropped straight down toward his face.
     Forgetful of the metal cylinder wall, he flinched away. The creature struck the transparent metal and clung to it. Jason had the perfect opportunity to examine it in every detail.
     It was almost too horrible to be believable. As though it were a bearer of death stripped to the very essentials. A mouth that split the head in two, rows of teeth, serrated and pointed. Leathery, claw-tipped wings, longer claws on the limbs that tore at the metal wall. Terror rose up in Jason as he saw that the claws were tearing gouges in the transparent metal. Wherever the creature’s saliva touched, the metal clouded and chipped under the assault of the teeth.
     Logic said these were just scratches on the thick tube. They couldn’t matter. But blind, unreasoning fear sent Jason curling away as far as he could. Shrinking inside himself, seeking escape.
     Only when the flying creature began dissolving did he realize the nature of the room outside. Sprays of steaming liquid came from all sides, raining down until the cylinders were covered. After one last dash of its jaws, the Pyrran animal was washed off and carried away. The liquid drained away through the floor and a second and third shower followed.

From DEATHWORLD by Harry Harrison (1960)

(ed note: Our intrepid heroes are part of the first moon exploration mission)

      The prospect ahead was not exactly strange, of course. Shandara had remarked several times in the last four weeks that a man who had seen any of the moon had seen all of it. A good many others had agreed with him. Even Ridging, whose temperament kept him normally expecting something new to happen, was beginning to get a trifle bored with the place. It wasn’t even dangerous; he knew perfectly well what exposure to vacuum would mean, but checking spacesuit and air-lock valves had become a matter of habit long before.

     Cosmic rays went through plastic suits and living bodies like glass, for the most part ineffective because unabsorbed; meteors blew microscopic holes through thin metal, but scarcely marked spacesuits or hulls, as far as current experiences went; the "dust-hidden crevasses” which they had expected to catch unwary men or vehicles simply didn’t exist—the dust was too dry to cover any sort of hole, except by filling it completely. The closest approach to a casualty suffered so far had occurred when a man had missed his footing on the ladder outside the Albireo’s air lock and narrowly avoided a hundred and fifty foot fall.

     Still, Shandara was being cautious. His eyes swept the ground ahead oi their tracks, and his gauntleted hands rested lightly on brake and steering controls as the tractor glided ahead.

     Harpalus and the relay station were out of sight now. Another glance behind assured Ridging of that. For the first time in weeks he was out of touch with the rest of the group, and for the first time he wondered whether it was such a good idea. Orders had been strict; the radius of exploration settled on long before was not to be exceeded. Ridging had been completely in favor of this; but it was his own instruments which had triggered the change of schedule.

     One question about the moon to which no one could more than guess an answer in advance was that of its magnetic field. Once the group was on the surface it had immediately become evident that there was one, and comparative readings had indicated that the south magnetic pole—or a south magnetic pole—lay a few hundred miles away. It had been decided to modify the program to check the region, since the last forlorn chance of finding any trace of a gaseous envelope around the moon seemed to lie in auroral investigation.

     It was only about three and a half hours after leaving the tractor, therefore, that the two men reached the peak they had selected, and looked out over the great mailed plain of Plato. They couldn't see all of it, of course; Plato is a hundred kilometers across, and even from a height of two thousand meters the farther side of the floor lies below the horizon. The opposite rim could be seen, of course, but there was no easy way to tell whether any of the peaks visible there were as high as the one from which the men saw them. It didn’t really matter; this one was high enough for their purposes.

     "All right,” he said, as he straightened up after closing the last switch, "when do we go down, and how long do we take?”
     "Go down where?” asked Shandara innocently.
     "Down to the crater floor, I suppose. I’m sure you don’t see enough to satisfy you from here. It’s just an ordinary crater, of course, but it’s three times the diameter of Harpalus even if the walls are less than half as high, and you’ll surely want to see every square meter of the floor.”
     "I’ll want to see some of the floor, anyway.” Shandara’s tone carried feeling even through the suit radios. It’s nice of you to realize that we have to go down. I wish you realized why.”
     "You mean … you mean you really expect to climb down there?” Ridging, in spite of his knowledge of the other's interests, was startled. "I didn't really mean—”
     "I didn’t think you did. You haven’t looked over the edge once.”

     Ridging repaired the omission, letting his gaze sweep carefully over the grayish plain at the foot of the slope. He knew that the floor of Plato was one of the darker areas on the moon, but had never supposed that this fact constituted a major problem.

     "I don’t get it,” he said at last. "I don't see anything. The floor is smoother than that of Harpalus, I’d say, but I’m not really sure even of that, from this distance. It’s a couple of kilos down and I don’t know how far over.”
     "You brought the map.” It was not a question.
     "Of course.”
     "Look at it. It’s a good one.” Ridging obeyed, bewildered. The map was good, as Shandara had said; its scale was sufficient to show Plato some fifteen centimeters across, with plenty of detail. It was basically an enlargement of a map published on Earth, from telescopic observations; but a good deal of detail had been added from photographs taken during the approach and landing of the expedition. Shandara knew that; it was largely his own work.
     As a result, Ridging was not long in seeing what his companion meant. The map showed five fairly large craterlets within Plato, and nearly a hundred smaller features.
     Ridging could see none of them from where he stood.
     He looked thoughtfully down the slope, then at the other man.

     "I begin to see what you mean. Did you expect something like this? Is that why you wanted to come here? Why didn’t you tell me?”
     "I didn’t expect it, though I had a vague hope. A good many times in the past, observers have reported that the features on the floor of this crater were obscured. Dr. Pickering, at the beginning of the century, thought of it as an active volcanic area; others have blamed the business on clouds—and others, of course, have assumed the observers themselves were at fault, though that is pretty hard to justify. I didn’t really expect to get a chance to check up on the phenomenon, but I’m sure you don’t expect me to stay up here now.”

     It was the last few hundred meters of descent that began to furnish something of interest. Shandara was picking his way down an unusually uninviting bit of slope when Ridging, who had already negotiated it, spoke up sharply.
     "Shan ! Look at the stars over the northern horizon! Isn’t there some sort of haze? The sky around them looks a bit lighter.” The other paused and looked.
     "You’re right. But how could that be? There couldn’t suddenly be enough air at this level—gases don't behave that way. Van Maanen’s star might have an atmosphere twenty meters deep, but the moon doesn’t and never could have.”
     "There’s something between us and the sky.”
     "That I admit; but I still say it isn’t gas. Maybe dust—”
     "What would hold it up? Dust is just as impossible as air.”
     "I don’t know. The floor's only a few yards down—let’s not stand here guessing.” They resumed their descent.

     There was something blocking vision; the horizon was no longer visible, nor could the stars be seen for a few degrees above where it should have been. Neither man would have had the slightest doubt about the nature of the obscuring matter had he been on Earth; it bore every resemblance to dust. It had to be dust.

     But it couldn’t be. Granted that dust can be fine enough to remain suspended for weeks or months in Earth’s atmosphere when a volcano like Krakatoa hurls a few cubic miles of it aloft, the moon had not enough gas molecules around it to interefere with the trajectory of a healthy virus particle—and no seismometer in the last four weeks had registered crustal activity even approaching the scale of vulcanism. There was nothing on the moon to throw the dust up, and even less to keep it there.

     "Meteor splash?"’ Shandara made the suggestion hesitantly, fully aware that while a meteor might raise dust it could never keep it aloft. Ridging did not bother to answer, and his friend did not repeat the suggestion.

     The sky straight overhead seemed clear as ever; whatever the absorbing material was it apparently took more than the few feet above them to show much effect. That could not be right, though, Ridging reflected, if this stuff was responsible for hiding the features which should have been visible from the crater rim. Maybe it was thicker farther in. If so, they’d better go on—there might be some chance of collecting samples after all.

     The surface was fairly smooth, though a pattern of minute cracks suggestive of the joints formed in cooling basalt covered it almost completely. These were not wide enough even to constitute a tripping danger, and the men ignored them for the time being, though Ridging made a mental note to get a sample of the rock if he could detach one.

     The obscuration did thicken as they progressed, and by the time they had gone half a dozen kilometers it was difficult to see the crater wall behind them. Looking up, they saw that all but the brighter stars had faded from view even when the men shaded their eyes from the sunlit rock around them.

     Human instincts being what they are, the solution to the mystery followed automatically and immediately. A man who fails, for any reason, to see as clearly as he expects usually rubs his eyes—if he can get at them. A man wearing goggles or a space helmet may just possibly control this impulse, but he follows the practically identical one of wiping the panes through which he looks. Ridging did not have a handkerchief within reach, of course, and the gauntlet of a spacesuit is not one of the best windshield wipers imaginable; but without giving a single thought to the action, he wiped his face plate with his gauntlet.

     Had there been no results he would not have been surprised; he had no reason to expect any. He would probably have dismissed the matter, perhaps with a faint hope that his companion might not have noticed the futile gesture. However, there were results. Very marked ones.

     The points where the plastic of the gauntlet actually touched the face plate were few; but they left trails all the way across—opaque trails. Surprised and still not thinking, Ridging repeated the gesture in an automatic effort to wipe the smears of whatever it was from his helmet; he only made matters worse. He did not quite cover the supposedly transparent area with glove trails—but in the few seconds after he got control of his hand the streaks spread and merged until nothing whatever was visible. He was not quite in darkness; sunlight penetrated the obscuring layer, but he could not see any details.

     "Shan!” The cry contained almost a note of panic. "I can’t see at all. Something’s covering my helmet!” The cartographer straightened up from his camera and turned toward his friend.

     "How come? You look all right from here. I can’t see too clearly, though—”

     Reflexes are wonderful. It took about five seconds to blind Shandara as thoroughly as Ridging. He couldn’t even find his camera to close the shutter.

     "You know,” said Ridging thoughtfully after two or three minutes of heavy silence, "we should have been able to figure all this out without coming down here.”
     "Oh, it’s plain as anything—”
     "Nothing, and I mean nothing, is plain right now.”
     "I suppose a map maker would joke while he was surveying Gehenna. Look, Shan, we have reason to believe there’s a magnetic storm going on, which strongly suggests charged particles from the sun. We are standing, for practical purposes, on the moon’s south magnetic pole. Most level parts of the moon are covered with dust—but we walked over bare rock from the foot of the rim to here. Don’t those items add up to something?”
     "Not to me.”
     "Well, then, add the fact that electrical attraction and repulsion are inverse square forces like gravity, but involve a vastly bigger proportionality constant.”
     “If you’re talking about scale I know all about it, but you still don't paint me a picture.”
     "All right. There are, at a guess, protons coming from the sun. They are reaching the moon’s surface here—virtually all of them, since the moon has a magnetic field but no atmosphere. The surface material is one of the lousiest imaginable electrical conductors, so the dust normally on the surface picks up and keeps a charge. And what, dear student, happens to particles carrying like electrical charges?”
     "They are repelled from each other.”
     "Head of the class. And if a hundred-kilometer circle with a rim a couple of kilos high is charged all over, what happens to the dust lying on it?

     Shandara did not answer; the question was too obviously rhetorical. He thought for a moment or two, instead, then asked, "How about our face plates?”
     Ridging shrugged—a rather useless gesture, but the time for fighting bad habits had passed some minutes before.
     "Bad luck. Whenever two materials rub against each other, electrons come loose. Remember your rubber-and-cat-fur demonstrations in grade school. Unless the materials are of identical electronic make-up, which for practical purposes means unless they are the same substance, one of them will hang onto the electrons a little—or a lot—better than the other, so one will have a negative net charge and the other a positive one. It’s our misfortune that the difference between the plastic in our face plates and that in the rest of the suits is the wrong way; when we rubbed the two, the face plates picked up a charge opposite to that of the surrounding dust—probably negative, since I suppose the dust is positive and a transparent material should have a good grip on its electrons.”
     "Then the rest of our suits, and the gloves we wiped with in particular, ought to be clean.”
     "Ought to be. I’d like nothing better than a chance to check the point.”
     "Well, the old cat’s fur didn’t stay charged very long, as I remember. How long will it take this to leak off, do you think?”
     "Why should it leak off at all ?"
     "What? Why, I should think—Hm-m-m.” Shandara was silent for a moment. "Water is pretty wonderful stuff, isn’t it?”
     "Yep. And air has its uses, too.”
     "Then we’re … Ridge, we’ve got to do something. Our air will last indefinitely, but you still can’t stay in a spacesuit too long.”
     "I agree that we should do something; I just haven’t figured out what. Incidentally, just how sure are you that our air will last? The windows of the regenerators are made, as far as I know, of the same plastic our face plates are. What'll you bet you’re not using emergency oxygen right now?”
     "I don’t know—I haven’t checked the gauges.”
     "I’ll say you haven’t. You won’t, either; they’re outside your helmet.”
     "But if we're on emergency now, we could hardly get back to the tractor starting this minute. We’ve got to get going.”
     "Which way?”
     "Toward the rim!”
     "Be specific, son. Just which way is that? And please don’t point; it’s rude, and I can't see you anyway.”
     "All right, don’t rub it in. But Ridge, what can we do?”
     "While this stuff is on our helmets, and possibly our air windows, nothing. We couldn’t climb even if we knew which way the hills were. The only thing which will do us the least good is to get this dust off us; and that will do the trick. As my mathematical friends would say, it is necessary and sufficient.”
     "All right, I’ll go along with that. We know that the material the suits are made of is worse than useless for wiping, but wiping and electrical discharge seem to be the only methods possible. What do we have which by any stretch of the imagination might do either job?”
     "What is your camera case made of?” asked Ridging.
     "As far as I know, same as the suits. It’s a regular clip-on carrier, the sort that came with the suits— remember Tazewell’s remarks about the dividends AirTight must have paid when they sold the suits to the Project? It reminded me of the old days when you had to buy a lot of accessories with your automobile whether you wanted them or not—”
     "All right, you’ve made your point. The case is the same plastic. It would be a pretty poor wiper anyway; it’s a box rather than a bag, as I remember. What else is there?”

     The silence following this question was rather lengthy. The sad fact is that spacesuits don’t have outside pockets for handkerchiefs. It did occur to Ridging after a time that he was carrying a set of geological specimen bags; but when he finally did think of these and took one out to use as a wiper, the unfortunate fact developed that it, too, left the wrong charge on the face plate of his helmet. He could see the dear, smooth plastic of the bag as it passed across the plate, but the dust collected so fast behind it that he saw nothing of his surroundings. He reflected ruefully that the charge to be removed was now greater than ever. He also thought of using the map, until he remembered that he had put it on the ground and could never find it by touch.

     "I never thought,” Shandara remarked after another lengthy silence, "that I’d ever miss a damp rag so badly. Blast it, Ridge, there must be something.”
     "Why? We’ve both been thinking without any result that I can see. Don’t tell me you’re one of those fellows who think there’s an answer to every problem.”
     "I am. It may not be the answer we want, but there is one. Come on, Ridge, you’re the physicist; I’m just a high-priced picture-copier. Whatever answer there is, you’re going to have to furnish it; all my ideas deal with maps, and we’ve done about all we can with those at the moment.”
     "Hm-m-m. The more I think, the more I remember that there isn’t enough fuel on the moon to get a rescue tractor out here, even if anyone knew we were in trouble and could make the trip in time. Stillwait a minute; you said something just then. What was it?”
     "I said all my ideas dealt with maps, but—”
     "No; before that.”
     "I don’t recall, unless it was that crack about damp rags, which we don’t have.”

     "That was it. That’s it, Shan; we don’t have any rags, but we do have water.”
     "Yes—inside our spacesuits. Which of us opens up to save the other?”
     "Neither one. Be sensible. You know as well as I do that the amount of water in a closed system containing a living person is constantly increasing; we produce it, oxidizing hydrogen in the food we eat. The suits have driers in the air cycler or we couldn’t last two hours in them.”
     "That’s right; but how do you get the water out? You can’t open your air system.”
     "You can shut it off, and the check valve will keep air in your suit—remember, there’s always the chance someone will have to change emergency tanks. It’ll be a job, because we won’t be able to see what we’re doing, and working by touch through spacesuit gauntlets will be awkward as anything I’ve ever done. Still, I don't see anything else."
     "That means you’ll have to work on my suit, then, since I don’t know what to do after the line is disconnected. How long can I last before you reconnect? And what do you do, anyway? You don’t mean there’s a reservoir of liquid water there, do you ?”
     "No, it's a calcium chloride drier; and it should be fairly moist by now— You’ve been in the suit for several hours. It’s in several sections, and I can take out one and leave you the others, so you won’t suffer from its lack. The air in your suit should do you for four or five minutes, and if I can’t make the disconnection and disassembly in that time I can’t do it at all. Still, it’s your suit, and if I do make a mistake it’s your life; do you want to take the chance?”
     "What have I to lose? Besides, you always were a pretty good mechanic —or if you weren’t, please don’t tell me. Get to work.”
     "All right.”

     As it happened, the job was not started right away, for there was the minor problem of finding Shandara to be solved first. The two men had been perhaps five yards apart when their face plates were first blanked out, but neither could now be sure that he hadn’t moved in the meantime, or at least shifted around to face a new direction. After some discussion of the problem, it was agreed that Shandara should stand still, while Ridging walked in what he hoped was the right direction for what he hoped was five yards, and then start from wherever he found himself to quarter the area as well as he could by length of stride. He would have to guess at his turns, since even the sun no longer could penetrate the layer of dust on the helmets.
     It took a full ten minutes to bump into his companion, and even then he felt undeservedly lucky.

     Shandara lay down, so as to use a minimum of energy while the work was being done. Ridging felt over the connection several times until he was sure he had them right—they were, of course, designed to be handled by spacesuit gauntlets, though not by a blindfolded operator. Then he warned the cartographer, closed the main cutoffs at helmet and emergency tanks to isolate the renewer mechanism, and opened the latter. It was a simple device, designed in throwaway units like a piece of electronic gear, with each unit automatically sealing as it was removed—a fortunate fact if the alga culture on which Shandara’s life for the next few hours depended was to survive the operation.
     The calcium chloride cells were easy to locate; Ridging removed two of the half dozen to be on the safe side, replaced -and reassembled the renewer, tightened the connections, and reopened the valves.
     Ridging now had two cans of calcium chloride. He could not tell whether it had yet absorbed enough water actually to go into solution, though he doubted it; but he took no chances. Holding one of the little containers carefully right side up, he opened its perforated top, took a specimen bag and pushed it into the contents. The plastic was not, of course, absorptive—it was not the first time in the past hour he had regretted the change from cloth bags—but the damp crystals should adhere, and the solution if there was any would wet it. He pulled out the material and applied it to his face plate.
     It was not until much later that he became sure whether there was any liquid. For the moment it worked, and he found that he could see; he asked no more. Hastily he repeated the process on Shandara’s helmet, and the two set out rapidly for the rim. They did not stop to pick up camera or map.
     Travel is fast on the moon, but they made less than four hundred meters. Ihen the face plates were covered again. With a feeling of annoyance they stopped, and Ridging repeated the treatment.
     This time it didn’t work.

     "I supposed you emptied the can while you were jumping,” Shandara remarked in an annoyed tone. "Try the other one.”
     "I didn’t empty anything; but I’ll try.” The contents of the other container proved equally useless, and the cartographer’s morale took another slump.
     "What happened?” he asked. "And please don’t tell me it’s obvious, because you certainly didn’t foresee it.”
     "I didn’t, but it is. The chloride dried out again.”
     "I thought it held onto water.”
     "It does, under certain conditions. Unfortunately its equilibrium vapor pressure at this temperature is higher than the local barometer reading. I don’t suppose that every last molecule of water has gone, but what’s left isn’t sufficient to make a conductor. Our face plates are holding charge again—maybe better than before; there must be some calcium chloride dust on them now, though I don’t know offhand what effect it would have.”
     "There are more chloride cartridges in the cyclers.”
     "You have four left, which would get us maybe two kilos at the present rate. We can’t use mine, since you can’t get them out; and if we use all yours you’d never get up the rim. Drying your air isn’t just a matter of comfort, you know; that suit has no temperature controls—it depends on radiation balance and insulation. If your perspiration stops evaporating, your inner insulation is done; and in any case, the cartridges won’t get us to the rim.”
     "In other words you think we’re done—again.”
     "I certainly don’t have any more ideas.”
     "Then I suppose I’ll have to do some more pointless chattering. If it gave you the last idea, maybe it will work again.”
     "Go ahead. It won’t bother me. I’m going to spend my last hours cursing the character who used a different plastic for the face plate than he did for the rest of these suits.”

(ed note: Scene shifts to several hours later, back at home base. Shandara and Ridging have managed to escape the electrostatic dust. They are explaining to the mission commander what they did.)

     "All right,” Tazewell snapped as the geophysicist paused. "I’m supposed to ask you what you did then. You’ve just told me that that handkerchief of yours is a good windshield wiper; I'll admit I don't see how. I'll even admit I'm curious, if it’ll make you happy.”
     "It's not a handkerchief, as I said. It’s a specimen bag.”
     "I thought you tried those and found they didn’t work—left a charge on your face plate like the glove.”
     "It did. But a remark I made myself about different kinds of plastic in the suits gave me another idea. It occurred to me that if the dust was, say, positively charged—”
     "Probably was. Protons from the sun.”
     "All right. Then my face plate picked up a negative, and my suit glove a positive, so the dust was attracted to the plate.
     "Then when we first tried the specimen bag, it also charged positively and left negative on the face plate.
     "Then it occurred to me that the specimen bag rubbed by the suit might go negative; and since it was fairly transparent, I could—”
     "I get it! You could tie it over your face plate and have a windshield you could see through which would repel the dust.”
     "That was the idea. Of course, I had nothing to tie it with; I had to hold it.”
     "Good enough. So you got a good idea out of an idle remark.”
     "Two of them. The moisture one came from Shan the same way.”
     "But yours worked.” Ridging grinned.
     "Sorry. It didn't. The specimen bag still came out negative when rubbed on the suit plastic—at least it didn’t do the face plate any good.”

     Tazewell stared blankly, then looked as though he were about to use violence.
     "All right! Let’s have it, once and for all.”
     "Oh, it was simple enough. I worked the specimen bag—I tore it open so it would cover more area—across my face plate, pressing tight so there wouldn’t be any dust under it.”
     "What good would that do? You must have collected more over it right away.”
     "Sure. Then I rubbed my face plate, dust rag and all, against Shandara’s. We couldn’t lose; one of them was bound to go positive. I won, and led him up the rim until the ground charge dropped enough to let the dust stick to the surface instead of us. I'm glad no one was there to take pictures, though; I’d hate to have a photo around which could be interpreted as my kissing Shandara’s ugly face—even through a space helmet.”

From DUST RAG by Hal Clement (1956)

Cemetery Planets

RocketCat sez

If you're a writer, the point of fabulous planets is to be fabulous. If you novel is set on a planet about as exciting as the town of Resume Speed Flyover-State (population 230, 170, 78 and still growing!) you are starting out on the wrong foot. Grab your reader's attention with every trick you've got or get used to seeing your work on the clearance shelf.

And the old reliable attention-getter is Death. Tends to make people sit up and take notice, it does.

Sterile planets that never had life in the first place are a milli-credit a kilo-pack. And there really isn't any "death" when there was no "life" in the first place. So setting your novel on sterile planet is just as boring as setting it on any of the interchangeable faceless outer moons of the solar system. Astronomers may find them fascinating but to the great unwashed it is the big Ho-Hum. Same-old, same-old.

To play the Death card and perk up the reader's interest there has to have been something previously living. Say a planet with ruins belonging to an alien interstellar empire which went extinct before Terran fish decided to evolve into land creatures. This will take a bit of the glaze out of the reader's eye even if the empire and the alien species quietly died of old age after a long boring decadence. This is an "extinct" planet.

But if you want to kick it up a notch, have the species die abruptly and violently. A "murdered" planet. That will wake up the readers. Have their planets suffer the scars of cosmic civil war, with craters where cities used to be and lots of collateral damage. Some still glowing faintly blue with Cherenkov radiation. Even if the last bomb dropped a billion years ago, this will look like an allegory for our current times. Well, at least an allegory for readers who grew up during the Cold War and can remember Bert the Turtle advising them to "Duck and Cover." That film should have been about bending over to kiss your buns good-bye, but I digress.

You the writer can just imagine all the purple prose you can write about the arid lifeless landscape with skeletal wrecked buildings, skeletal burnt forests, and skeletal skeletons of alien unburied bodies.

To turn it up to 11, have your space explorers discover a murdered planet that apparently was murdered last Wednesday. And not from a civil war, but instead by Something From Outside. Indeed by Something that might still be lurking in the general area so GO TO BATTLE STATIONS RIGHT NOW AND DOUSE THAT LIGHT!!

Planets with no life are rather common (just look at our own solar system) and are rather boring. But nothing can beat the grim feeling of mortality engendered by examining a planet that used to have life. Especially if all the life died off rather abruptly.

A Forerunner planet is not too depressing if the culture basically died of old age. No more depressing than your average archeological dig. But if the entire planet still glows blue from an age-old nuclear armageddon, well, the explorers can't help but wonder if the political situation back home has taken a turn for the worse while they've been away.

If the survey team is lucky they will have advanced warning about the presence of a dead planet when astronomers light-years away detect necrosignatures.

How can planets die? Let me count the ways. The standard ways are:

...keeping in mind that most of these methods work equally well for a planetary civilization committing suicide or a planetary civilization exterminated by alien invaders. For more exotic apocalypses go here.


(ed note: in the ANTARES universe, starships move FTL by utilizing naturally-occurring "foldpoint." The planet Alta around the star Valeria was colonized from the planet New Providence around the star Napier. One fine day, Valeria's sole foldpoint vanishes. Valeria is cut off from the other human worlds

120 years later, the people at Valeria observe the star Antares going supernova as the wave front of the explosion reaches Valeria. Since Antares is exactly 120 light-years away, astronomers quickly realize the supernova is the reason the foldpoint vanished. And the distance is the reason why the foldpoint has abruptly reappeared.

An expedition to their mother world of New Providence is set up. But they realize the results will be grim. New Providence is only 15 light-years from Antares, so the radiation from the supernova sterilized the entire New Providence system. Hopefully they had at least one foldpoint that was not disrupted by the supernova, otherwise three billion people died horribly.

When the Valeria expedition reaches New Providence, they do expect to see all the cities abandoned, and all plant & animal life dead. What they found was a very rude surprise)

      Drake ordered Discovery to full alert twenty days and sixteen hours after leaving the foldpoint. As the General Quarters alarms wailed through the ship, New Providence was a blue-white marble on the main control room viewscreen. Off to one side was Laertes, New Providence’s rather sizable moon, a gray-white sphere that early New Providential poets had compared to Earth’s Luna.
     Shortly after the fleet had rounded Napier, Drake had met with Discovery’s scout pilots. “Before I commit the fleet to a close orbit of New Providence, gentlemen, I want to make damned sure that it’s safe to do so. Therefore, we will launch all four armed scouts while the fleet is still two million kilometers from the planet. Catherine and Drunkard will make a quick pass just outside the atmosphere to obtain reconnaissance views of two major urban areas on opposite sides of the globe. You can use the old maps to pick your targets. Flying Fool and Gossamer Gnat will follow close behind, but will decelerate sufficiently to enter opposing north-south polar orbits. I want at least two complete circuits of the planet before the fleet arrives.
     “Unless one of you waves us off, Discovery will take up a high guard, north-south parking orbit while City of Alexandria does the same close in. The two tankers will take up positions at the New Providence-Laertes L4 and L5 points, where they will act as ground-to-orbit communications relays, if and when such are required.”

     The scouts had spent the rest of the voyage refining the basic plan. By the time Discovery reached the specified distance from New Providence, they were eager to be on their way.
     “Are you ready, Lieutenant Hall?” Drake asked.
     “Ready, sir,” the commander of Discovery’s scout force said from out of the screen at Drake’s console. As in the approach to Conqueror, Drake planned to send his scouts in before risking any of the fleet’s ships. He wondered if he was again sending them to rendezvous with a derelict.
     “You may launch when ready,” Drake said to Hall.
     “Understood, Captain. We are launching now. Open hangar bay doors!”

     The first pictures from Catherine and Drunkard began coming in some four hours later. Discovery’s crew had been on full alert for all that time, scanning their instruments and checking their weapons. For all that time, the tension had been building aboard the battle cruiser. Every second that passed without someone detecting the presence of man on the ancestral home of all Altans brought with it a firmer realization that their worst fears might well be confirmed. New Providence had been a world of three billion souls; and now it was as silent as a tomb.
     The first long-range tele-views came from Scout Boat Drunkard. It showed a planetary limb, a blue ocean, and the unfamiliar shoreline of a continent. As they watched, the continent grew in size with surprising rapidity, an indication of the speed with which the scout was closing on the planet.
     “What is Drunkard’s target?” Drake asked.
     “Regensburg,” Lieutenant Cristobal answered. “The records indicate that it is the major metropolis in the northern hemisphere. Catherine will arrive five minutes later, and will over-fly a city named Terra Nova.”
     The view jumped once as Scout-Pilot Marman ordered a switch to a higher magnification. The scene was suddenly frozen on the screen as the computer chose a single frame from Drunkard’s orbital mapping camera. The view was of the outskirts of the city of Regensburg taken at a slant angle of 45 degrees.
     Regensburg had been built on a series of rolling, forested hills. The screen showed equal parts of city and forest. The forest was dead. Bare trunks jutted skyward, sprouting stick-like branches in geometric symmetry. Many trees had been uprooted by windstorms. Their corpses lay scattered randomly among the upright bodies of their brethren. In some areas, the tangle of deadwood approached jungle proportions, as if the natural process of decay had been halted.
     “No microorganisms,” Drake muttered to no one in particular. “The planet must be sterile.”
     He switched his gaze to the city. It, too, was the color of dead plants; and like the forest, showed signs of weather damage; yet with a degree of preservation unexpected in a hundred-year-old ruin.
     “Scout Marman reports his flyby complete. He is headed out into space,” Slater reported from the communicator’s station.
     “How many frames did he get?”
     “Fifty thousand, Captain, all received and ready for processing. Catherine reports coming up on Terra Nova.”

     Drake turned his attention back to the main viewscreen. Again, there was a view of the planet’s limb. Again, the camera was switched over to high magnification, and a single frame was frozen on the control room viewscreen. This time the view was centered on a large city. However, where Regensburg had looked as though its inhabitants had stepped away for a moment, Terra Nova was a shambles. Everywhere, blackened steel frameworks jutted skyward from piles of masonry, toppled towers lay where they had smashed across parked groundcars, and hollow shells stood guard over collapsed interiors. The sight of the destruction sent a shiver through Drake’s soul.
     “Some kind of out-of-control fire?” Argos Cristobal asked.
     “It was an out-of-control fire, all right,” Bethany Lindquist responded, her voice filled with horror. “Look at the way the outlying buildings all seem to have toppled away from the central point. I have seen that pattern before in history tapes. That city did not burn of its own accord. Someone exploded a nuclear weapon on it!

     It had taken the fleet four hours after the initial flybys to reach New Providence. For half that time, the expedition’s scientists had pored over the panoramic views transmitted by Drunkard and Catherine, or had watched the unfolding of still greater panoramas as the other two armed scouts took up their stations just outside the atmosphere. The additional observations confirmed what they had already surmised. New Providence was indeed a dead world.
     Everywhere they looked, they found desolation and the remains of once-living things. As far as could be seen from orbit, nothing lived on the surface of the planet. Nor had the world died peacefully. Terra Nova was not to the only city that had died by the sword. The orbital survey crews counted more than five hundred blast-damaged areas on the planet, including many that had been the victims of more than one strike.

From ANTARES DAWN by Michael McCollum (1986)

Scavenger World: Leaving aside companies like Probable Technologies, ICC and their professional xenoarchaeology-for-profit efforts, this is subverted; while there are any number of vultures happy to pick over cemetery worlds to loot them of recoverable goods or materials, or indeed of waiting around worlds about to become such worlds (i.e., in the throes of internal war or collapse) to get a good head start on the picking over, most of these are offworlders. Most major disasters either let people pick up in a decade or two, or else kill too many people too fast to let the survivors live into a scavenger-world scenario, at least not for long.


“It must be a beacon, a marker—but for whom—run by whom—?”

“Must it be run by anyone?” asked Rolth thoughtfully. “Remember Tantor—”

Tantor, the sealed city. Its inhabitants had been overwhelmed by a ghastly plague two centuries ago. Yes, he recalled Tantor well. Once he had flown above the vast bubble which enclosed it in an eternal prison for the safety of the galaxy, and had watched the ancient machines going about their business below, running a city in which no living thing walked or ever would walk again. Tantor had had its beacons too, and its appeals for help streaming into the skies mechanically long after the hands which had set them going had been dust. Behind those hills ahead might well rest another Tantor—it would explain the puzzle of a fair but deserted world.

From STAR RANGERS by Andre Norton, 1953.
Collected in STAR SOLDIERS (2001), currently a free eBook in the Baen free library.

Every so often in the kaleidoscope of life, they would be shown something they came to call a black world. They came close to the first one six months after the division.

They found themselves looking down on a planet which had once been like the others, but was now black waste and ruined cities. The mountains of the planet had jutted treeless into the sky like the exposed bones of a corpse, and the sky itself was black where once it had been blue and green and orange.

The seas which had been the womb of life were its final refuge, for there bacteria, the last things to survive, fought to consume the floating debris washed down by the flood Waters of a thousand years, and to turn it into an all-embracing scum which would s eventually suffocate even this activity.

It was a long time before they saw another world which had shared a similar fate, and they never approached so closely again.

From NOAH II by Roger Dixon (1970)

(ed note: The free trader crew of the Solar Queen purchase the rights to a planet in a Survey Auction. And quickly discover they've bought a pig in a poke.)

      THEY WERE ALL in the mess cabin again, the only space in the Queen large enough for the crew to assemble. Tang Ya set a reader on the table while Captain Jellico slit the packet and brought out the tiny roll of film it contained. Dane believed afterwards that few of them drew a really deep breath until it was fitted into place and the machine focused on the wall in lieu of the regular screen.
     “Planet—Limbo—only habitable one of three in a yellow star system—” the impersonal voice of some bored Survey clerk droned through the cabin.
     On the wall of the Queen appeared a flat representation of a three world system with the sun in the centre. Yellow sun—perhaps the planet had the same climate as Terra! Dane’s spirits soared. Maybe they were in luck—real luck.
     “Limbo—” that was Rip wedged beside him. “Man, oh, man, that’s no lucky name—that sure isn’t!”
     But Dane could not identify the title. Half the planets on the trade lanes had outlandish names didn’t they—any a Survey man slapped on them.
     “Co-ordinates—” the voice rippled out lines of formulae which Wilcox took down in quick notes. It would be his job to set the course to Limbo.
     “Climate—resembling colder section of Terra. Atmosphere—” more code numbers which were Tau’s concern. But Dane gathered that it was one in which human beings could live and work.

     The image in the screen changed. Now they might be hanging above Limbo, looking at it through their own view ports. And that vision was greeted with at least one exclamation of shocked horror.

     For there was no mistaking the cause of those brown-grey patches disfiguring the land masses. It was the leprosy of war—a war so vast and terrible that no Terran could be able to visualize its details.
     “A burnt off!” that was Tau, but above his voice rose that of the Captain’s.
     “It’s a filthy trick!”

     “Hold it!” Van Rycke’s rumble drowned out both outbursts, his big hand shot out to the reader’s control button. “Let’s have a close up. North a bit, along those burn scars—”
     The globe on the screen shot towards them, enlarging so that its limits vanished and they might have been going in for a landing. The awful waste of the long ago war was plain, earth burned and tortured into slag, maybe still even poisonous with radioactive wastes. But the Cargo-Master had not been mistaken, along the horrible scars to the north was a band of strangely tinted green which could only be vegetation. Van Rycke gave a sigh of satisfaction.
     “She isn’t a total loss—” he pointed out.
     “No,” retorted Jellico bitterly, “probably shows just enough life so we can’t claim fraud and get back our money.”

     “Forerunner ruins?” the suggestion came from Rip, timidly as if he felt he might be laughed down.
     Jellico shrugged. “We aren’t museum men,” he snapped. “And where would we have to go to make a deal with them—off Naxos anyway. And how are we going to lift from here now without cash for the cargo bond?”
     He had hammered home every bad point of their present situation. They owned ten-year trading rights to a planet which obviously had no trade—they had paid for those rights with the cash they needed to assemble a cargo. They might not be able to lift from Naxos. They had taken a Free Trader’s gamble and had lost.

     Only the Cargo-Master showed no dejection. He was still studying the picture of Limbo.
     “Let’s not go off with only half our jets spitting,” he said mildly. “Survey doesn’t sell worlds which can’t be exploited—”
     ”Not to the Companies, no,” Wilcox commented, “but who’s going to listen to a kick from a Free Trader—unless he’s Cofort!”
     “I still say,” Van Rycke continued in the same even tone, “that we ought to explore a little farther—”
     “Yes?” Jellico’s eyes held a spark of smouldering anger. “You want us to go there and be stranded? She’s burnt off—so she’s got to be written off our books. You know there’s never any life left on a Forerunner planet that was assaulted—
     “Most of them are just bare rock now,” Van Rycke said reasonably. “It looks to me as if Limbo didn’t get the full treatment. After all—what do we know about the Forerunners—precious little! They were gone centuries, maybe even thousands of years, before we broke into space. They were a great race, ruling whole systems of planets, and they went out in a war which left dead worlds and even dead suns swinging in its wake. All right.
     “But maybe Limbo was struck in the last years of that war, when their power was on the wane. I’ve seen the other blasted worlds—Hades and Hel, Sodom, and Satan, and they’re nothing but cinders. This Limbo still has vegetation. And because it isn’t as badly hit as those others I think we might just have something—

     He is winning his point, Dane told himself—noticing the change of expression on the faces around the table. Maybe it’s because we don’t want to believe that we’ve been taken so badly, because we want to hope that we can win even yet. Only Captain Jellico looked stubbornly unconvinced.
     “We can’t take the chance,” he repeated, his lips in an obstinate line. “We can fuel this ship for one trip—one trip. If we make it to Limbo and there’s no return cargo—well,” he slapped his hand on the table, “you know what that will mean—dirt-side for us!”
     Steen Wilcox cleared his throat with a sharp rasp which drew their attention. “Any chance of a deal with Survey?” he wanted to know.
     Kamil laughed, scorn more than amusement in the sound. ”Do the Feds ever give up any cash once they get their fingers on it?” he inquired.

     No one answered him until Captain Jellico got to his feet, moving heavily as if some of the resilience had oozed out of his tough body.
     “We’ll see them in the morning. You willing to try it, Van?”
     The Cargo-Master shrugged. “All right, I’ll tag along. Not that it’ll do us any good.”
     “Blasted—right off course—”
     Dane stood again at the open hatch looking out into a night made almost too bright by Naxos’ twin moons. Kamil’s words were not directed to him, he was sure. And a moment later that was confirmed by an answer from Rip.

     “I don’t call luck bad, man, ’til it up and slaps me in the face. Van had an idea—that planet wasn’t blasted black. You’ve seen pictures of Hel and Sodom, haven’t you? They’re cinders, as Van said. This Limbo, now—it shows green. Did you ever think, Ali, what might happen if we walked on to a world where some of the Forerunners’ stuff was lying around?”
     “Hm—” the idea Rip presented struck home. “But would trading rights give us ownership of such a find?”
     “Van would know—that’s part of his job. Why—” for the first time Rip must have sighted Dane at the hatch, “here’s Thorson. How about it, Dane? If we found Forerunner material, could we claim it legally?”
     Dane was forced to admit that he didn’t know. But he determined to hunt up the answer in the Cargo-Master’s tape library of rules and regulations.
     “I don’t think that the question has ever come up,” he said dubiously. “Have they ever found usable Forerunner remains—anything except empty ruins? The planets on which their big installations must have been are the burnt off ones—

     “I wonder,” Kamil leaned back against the hatch door and looked at the winking lights of the town, “what they were like. All of the strictly human races we have encountered are descended from Terran colonies. And the five non-human ones we know are all as ignorant of the Forerunners as we are. If they left any descendants we haven’t contacted them yet. And—” he paused for a long moment before he added, “did you ever think it is just as well we haven’t found any of their installations? It’s been exactly ten years since the Crater War—
     His words trailed off into a thick silence which had a faint menacing quality Dane could not identify, though he understood what Kamil must be aiming at. Terrans fought, viciously, devastatingly. The Crater War on Mars had been only the tail end of a long struggle between home planet and colonist across the void. The Federation kept an uneasy peace, the men of Trade worked frantically to make that permanent before another and more deadly conflict might wreck the whole Service and perhaps end their own precarious civilization.
     What would happen if weapons such as the Forerunners had wielded in their last struggle, or even the knowledge of such weapons, fell into the wrong Terran hands? Would Sol become a dead star circled by burnt off cinder worlds?
     “Sure, it might cause trouble if we found weapons,” Rip had followed the same argument. “But they had other things besides arms. And maybe on Limbo—”

From SARGASSO OF SPACE by Andre Norton (1955)

(ed note: Brad is showing Ivo views from planets thousands of light-years away by using handwavium technology called a Macroscope)

"You're being subjective," Brad said. "Compare these."

And the screen showed an angelic humanoid face, feminine and altogether lovely. The eyes were great and golden, the mouth small and sweet. Above the still features flowed a coiffure of down, neither hair nor feathers, greenish but softly harmonious. Below the face a silken robe covered a slender body, but Ivo could tell from its configuration that the gentle curves of the torso were not precisely mammalian. It was as though a human woman had evolved into a more sublime personage, freed from the less esthetic biological functions.

It was a painting; as Brad decreased the magnification the frame came into view, then the columns and arches of an elegant setting. A museum, clean and somber, styled by a master architect.

"Intelligent, civilized, beautiful," Ivo murmured. "But where are the living ones?"

"There are no living creatures on Planet Mbsleuti. This is a royal tomb, as nearly as we can ascertain — one of the few to be buried deeply enough to endure."

"Endure what?"

Suddenly the scene was a heaving sea of sludge, breaking against a barren beach. Ivo could almost smell the contamination of the smoky atmosphere.

"Total pollution," Brad said. "Earth, air, water. We have analyzed the content and determined that all of it is artificial. They became dependent on their machines for their existence, and could not control the chemical and atomic waste products. Want to bet where they got their fresh meat, just before the end? But it only hastened their extinction as a species."

The picture of the royal woman was back, mercifully, but Ivo still saw her devastated world. "Because they overextended their resources?" he asked, requiring no answer. "Would not limit themselves until Nature had to do it for them?" He shook his head.

From MACROSCOPE by Piers Anthony (1969)

As if beckoned by those who had gone before, I half-floated between the titanic snowdrifts, quivering and afraid, into the sightless vortex of the unimaginable.

Screamingly sentient, dumbly delirious, only the gods that were can tell. A sickened, sensitive shadow writhing in hands that are not hands, and whirled blindly past ghastly midnights of rotting creation, corpses of dead worlds with sores that were cities, charnel winds that brush the pallid stars and make them flicker low. Beyond the worlds vague ghosts of monstrous things; half-seen columns of unsanctifled temples that rest on nameless rocks beneath space and reach up to dizzy vacua above the spheres of light and darkness. And through this revolting graveyard of the universe the muffled, maddening beating of drums, and thin, monotonous whine of blasphemous flutes from inconceivable, unlighted chambers beyond Time; the detestable pounding and piping whereunto dance slowly, awkwardly, and absurdly the gigantic, tenebrous ultimate gods the blind, voiceless, mindless gargoyles whose soul is Nyarlathotep.

From NYARLATHOTEP by H. P. Lovecraft (1920 )

As has happened so often in the past, the challenge may be too great. We may establish colonies on the planets, but they may be unable to maintain themselves at more than a marginal level of existence, with no energy left over to spark any cultural achievements.

History has one parallel as striking as it is ominous, for long ago the Polynesians achieved a technical tour-de-force which may well be compared with the conquest of space. By establishing regular maritime traffic across the greatest of oceans, writes Toynbee, they "won their footing on the specks of dry land which are scattered through the watery wilderness of the Pacific almost as sparsely as the stars are scattered through space."

But the effort defeated them at last, and they relapsed into primitive life. We might never have known of their astonishing achievement had it not left, on Easter Island, a memorial that can hardly be overlooked.

There may be many Easter Islands of space in the aeons to come — abandoned planets littered not with monoliths but with the equally enigmatic debris of another defeated technology.

From PROFILES OF THE FUTURE by Arthur C. Clarke

I met a traveler from an antique land
Who said: Two vast and trunkless legs of stone
Stand in the desert. Near them on the sand,
Half sunk, a shatter'd visage lies, whose frown
And wrinkled lip and sneer of cold command
Tell that its sculptor well those passions read
Which yet survive, stamp'd on these lifeless things,
The hand that mock'd them and the heart that fed.
And on the pedestal these words appear:
"My name is Ozymandias, king of kings:
Look on my works, ye mighty, and despair!"
Nothing beside remains: round the decay
Of that colossal wreck, boundless and bare,
The lone and level sands stretch far away.

From "OZYMANDIAS" by Percy Bysshe Shelley (1818)

(ed note: Percy Shelley and his friend Horace Smith were in a friendly competition to write a sonnet about the new statue of Ramesses II in the British Museum. Smith's sonnet is similar in story and moral point, but includes a science fiction bit about a hunter of the future looking at the ruins of London. Sort of like an 1800's version of the ending of Planet of the Apes.)

In Egypt's sandy silence, all alone,
Stands a gigantic Leg, which far off throws
The only shadow that the Desert knows:—
"I am great OZYMANDIAS," saith the stone,
"The King of Kings; this mighty City shows
"The wonders of my hand."— The City's gone,—
Nought but the Leg remaining to disclose
The site of this forgotten Babylon.

We wonder,—and some Hunter may express
Wonder like ours, when thro' the wilderness
Where London stood, holding the Wolf in chace,
He meets some fragment huge, and stops to guess
What powerful but unrecorded race
Once dwelt in that annihilated place

From OZYMANDIAS by Horace Smith (1818)

Thundering Worlds

If you are fixated on the concept of "bigger is better," then it is hard to beat the idea of a spaceship the size of a planet. Or a planet converted into a spaceship. TV Trope's entry is called Planet Spaceship. The most recent example being the movie The Wandering Earth.

Well, maybe if you converted a Ringworld into a Bussard Ramjet to make a starship one astronomical unit in radius. That would be bigger.

Hang on, you could turn a star into a Shkadov thruster and turn an entire freaking solar system into a spaceship. Please pardon me, I have to go lie down a minute, my head hurts.

A good example of a known star with an unusually high velocity Barnard's Star aka "Barnard's Runaway Star" or "Greyhound of the Skies". Astronomers measured the lateral speed and the radial velocity to calculate a space velocity of 142 km/s which is smokin'. And it is only 1.8 parsecs away (5.98 light-years), making it the fourth-closest star to the Sun.


      In The Sins of the Fathers it is discovered that the core of our galaxy has exploded—something that is in fact known to happen to galaxies (though the mechanism considered most likely by astronomers has changed since the stories were written). Since the radiation produced is expected to render planets uninhabitable throughout the galaxy, the only possible hope of safety lies in flight to another galaxy. And the only practical way to achieve such an escape for any sizable portion of humanity is to use the Earth itself as a single enormous spaceship.

     What would such a trip be like?

     First of all, let us admit that a certain amount of “magic” is required; in Sins, this is offered by some advanced and ostensibly friendly extraterrestrials. By “magic,” I simply mean things that we do not now know how to do—things that would require new physical principles or processes. Some may object to the use of such devices in science fiction, and still more in a speculative but essentially non-fictional article. But I think it would be rather arrogant to assume that we already know all the fundamental principles on which the universe operates. (Any elementary particle physicist, for example, is painfully aware that we don’t.) What is essential in science fiction, I think, is that new principles be introduced sparingly (only when necessary, and not too many at once) and carefully (with the new principles formulated in such a way that they don’t contradict any old principles in regions which have been verified by experiment). If this is done, the new principles appear not as magic, but as potentially valid extensions of what we now know—as potentially valid (and as “magical”) as relativity might have been if it had been dreamed up by a science fiction writer in 1800.

     The first new principle needed to move the Earth for the purposes of Sins is probably obvious: one that will enable faster-than-light travel (FTL). Only thus will it be possible to outrun the deadly radiation from the exploding core. It is sometimes said (though less often and less confidently now than it used to be, since Gerald Feinberg and others started talking about “tachyons”) that the special theory of relativity proves that FTL is impossible. I find it difficult to consider the usual arguments a real proof; they’re far too similar to others (demonstrably wrong) which I can construct by using the earlier theories which relativity replaced (or rather, expanded). I’ll say a bit more about this later; for now, the important thing is that I lay my cards on the table and tell just what new principles I assumed for the trip. The Rao-Chang drive, a particular form of FTL with certain assumed properties, is the first.

     The other two are new processes for producing acceleration. The Rao-Chang drive is essentially a means of producing a discontinuous jump from a sub-c (slower-than-light) to a super-c speed. Both above and below the jump, the Earth must be accelerated by direct application of force, and it must be accelerated to a rather large fraction of c before the Rao-Chang “tunneling” can even be attempted. A little calculation shows that any attempt to get the entire Earth up to such a speed by such mundane methods as liquid hydrogen or even fusion rockets is utterly hopeless. The Earth is big: it takes a mind-boggling amount of energy to move it very much. In Sins, Rao estimates that the required rate of annihilation, if matter could be converted completely to energy in a photon rocket, would be “roughly comparable to twenty-five Mt. Everests per second.” And conventional processes convert only a very small percentage of their fuel to useful energy.

     To have even a ghost of a chance, it will be necessary to have a drive which can convert matter with essentially complete efficiency. We know of one such process, but it requires half of the matter being annihilated to be antimatter, with positrons instead of electrons and antiprotons instead of protons. In Sins, I have assumed a similar process, called “induced annihilation,” which completely converts ordinary matter (without addition of antimatter) to radiant energy, enabling the Earth to use any of its own mass as fuel to run itself as a photon rocket.

     Even this uses a lot of mass. The total trip, with the story’s assumptions, would require a mass ratio (fueled load/payload = starting mass/surviving mass) of about fifty. For this and other reasons, something still better would be highly desirable. The something better I have assumed for the story is an “exhaustless” or “reactionless conversion process which may be thought of as converting mass directly to produce a unidirectional thrust with no exhaust or other energy wastage—i.e., all of the rest mass which is annihilated appears as kinetic energy of the remaining part. This gets the mass ratio down to about six. Such a process is clearly well outside present-day orthodox science; it would make theoretical physicists very uncomfortable (not a bad idea, now and then) since it implies limitations on the generality of both conservation of momentum and the second law of thermodynamics. However, since the exceptions to these venerable laws lie completely outside familiar regions of experience, my conscience does not bother me about using even this.

     But these things—the Rao-Chang, induced annihilation, and exhaustless conversion processes, together with their logical implications—are the only really new physics I have assumed in thinking about the trip contemplated in Sins. Given them, the consequences for people living on the Earth are determined by well-known physical principles such as those of gravitational fields and accelerations, however produced, and less completely understood applications such as atmosphere dynamics and plate tectonics. And thoseconsequences are awesome. The Kyyra might seem, at first glance, like omnipotent magicians if they can do the things I’ve mentioned. But all of it is subject to physical law, and despite the magicians’ best endeavors, the trip would be arduous beyond anything in human experience.

     Qualitatively, several effects come to mind immediately. The trip as advertised by the Kyyra is to be to the spiral galaxy M31 in Andromeda, some two million light-years hence. It starts out with the induced annihilation “rocket” drive thrusting along the axis, with the nozzle at the South Pole. A pole is chosen because of the Earth’s spin (which may well be stopped after the trip is underway, to facilitate steering); the south pole is chosen because M31 lies roughly north. The reaction begins at the surface and works in toward the center of the Earth. Since the force is initially applied to a small part of the Earth and must be transmitted to the rest of the planet, stresses are set up in the mantle and crust which, even if applied cautiously, can be expected to have “local” effects such as earthquakes, particularly along the boundaries of the continent-bearing plates (e.g., the well-known “ring of fire” surrounding the Pacific). These should subside once a steady thrust state has been achieved, but not until after some rearrangement has taken place.

     Operation of a super-rocket nozzle at the South Pole melts the polar cap, for starters, but that’s minor compared to other things that happen. The blast also annihilates or at least vaporizes and violently blows water and air which come into it. Such effects give a strong incentive—in addition to the one related to mass ratio—to use this rocket-like reaction for the shortest possible time. (In the story, the Kyyra need it only to get things started, after which it becomes feasible to use the exhaustless drive for almost the entire trip.)

     As the Earth moves away from the Sun, not only does the sky change (most prominently, the Sun and Moon are left behind), but the entire heating pattern of the planet changes. The Sun is replaced by controlled leakage from the internal reactions as the planet’s main thermal energy input. (Here, by the way, is where the necessity for essentially completely efficient conversion comes in. When core material is annihilated, the fraction of the released energy which flows out as heat must be very small. Otherwise, the energy reaching the surface would be several orders of magnitude greater than we’re now getting from the Sun, with such disastrous effects that I’d have nothing left to write about.) The fact that most of the heat reaching the surface would then be radiating outward from inside the Earth could, in itself, have relatively little effect on the atmosphere, which is already heated largely by re-radiation of solar energy from the surface. But it would surely have drastic effects on the oceans (which are not used to being heated from the bottom), such as destroying the marine ecosystem. Moreover, the atmosphere would be under attack from another angle: using up the Earth’s mass also reduces gravity, and that makes it increasingly possible for atmosphere to escape into space.

     Details of all these effects depend very much on how rapidly the Earth is accelerated to (and beyond) tunneling speed. (“Details” on a global scale, of course, will seem like far more than “details” to the people caught in them.) In fact, as it turns out, the relatively simple effects I’ve mentioned so far are complicated and overshadowed by other effects which are very directly connected with acceleration per se. Because acceleration of a vehicle, be it a freight elevator or the Earth, feels to the occupants exactly like a gravitational field, added vectorially to whatever real gravitational field may be present. In the case of the Earth, the real gravitational field is spherically symmetric and has a strength of 1 g (meaning it makes things accelerate toward the center of the Earth at 9.8 m/sec2). The “apparent gravitational field” which must be added to this if the whole planet is accelerating northward along the polar axis is not spherically symmetric. It is uniform, everywhere parallel to the polar axis (pointed south), and its magnitude is everywhere equal to the overall acceleration. This means that the effective gravitational field experienced by inhabitants of the accelerating Earth is distorted from spherical symmetry, and that has all kinds of dramatic effects. Just what those effects are, and how drastic, depends on how large an acceleration is used which also determines the overall time scale for the trip. So, to cite details, let’s pick a value or two.

     Assuming the means to be available, at least some people might prefer to use the highest acceleration they could stand, to get the ordeal over with as rapidly as possible. Stephen H. Dole (see Bibliography) suggests an upper limit of 1.25-1.5 g for the gravitational field of a human-habitable planet. If the acceleration used is 0.5 g (after a gradual build-up period, of course, to avoid drastic “jerk” effects which I’ll mention later), the effective gravitation everywhere on Earth initially lies somewhere between 0.5 g and 1.5 g so this seems to be a reasonable value to use for a trial upper limit of possible accelerations.

     This value of acceleration, if used throughout the accelerated parts of the trip, leads to a total trip time of some 7.5 years, plus any extra maneuvering time needed for settling into a new home in M31. Figuring the travel times is somewhat tricky; I did it approximately by using the graph of Figure 1, which shows some important aspects of the way in which the Rao-Chang drive is assumed to extend relativity. (If you don’t care how I did it, skip to the next paragraph.) I assume, for this paragraph only, that you have at least a nodding acquaintance with the relativistic effects of mass increase and time dilation. If not, perhaps the best way to give you an idea of what the graph says is through a couple of examples. At v/c ≈ 0 (meaning the kinds of speeds encountered in everyday experience), the factor y = 1, which simply means that mass and time are not significantly affected by such slow motion. At v/c = 0.8, or motion at 4/5 of the speed of light, though, the factor is 1.67. What this means is that an object with this speed is 1.67 times as resistant to acceleration, and ages 1.67 times more slowly, than when it is stationary or moving slowly. (This much is common garden-variety special relativity, well tested by experiment, much oversimplified in this brief description, and much better explained, though necessarily at greater length, in Spacetime Physics, cited in the Bibliography.)

     The new part of the graph, to the right of the asymptote at v/c =1, shows what is assumed to happen at speeds higher than c in a universe where the Rao-Chang drive works. (If such things interest you, you might notice that it’s derived from the sub-c relativistic form simply by changing one sign under the radical.) For example, at v/c =1.25 (=1/0.8), the factor is also 1.67—the same as at v/c = 0.8. The reason all this is important to estimating the trip time is that parts of the trip occur at speeds where these effects are significant, and they had to be taken into account; all trip times in this article are measured on the Earth, and not by an observer fixed in our galaxy. Moreover, when I say that the acceleration is maintained at 0.5 g, this also is measured on the Earth—for example, by standing on a bathroom scale at the North Pole. As for what this means, I could state it generally in rather complex terms, but for our purposes an example will probably do at least as well. The time (measured on Earth) to go from v = 2c to 3c (or vice versa) at constant acceleration is assumed to be the same as that required to go from 112 c to 1/3 c (or vice versa) at the same acceleration. Given these assumptions, trip times and distances covered can be estimated (as precisely as one cares to bother with) by dividing the graph up into small velocity intervals, using the average g to estimate time and distance in each interval, and adding up all the results.

     Skipping the gory details, I can summarize the results thus. The trip consists of the following main phases:

     1. Initial acceleration, to about 2/3 c. Thrust is started by induced annihilation with exhaust at the South Pole, soon superseded by the exhaustless direct conversion process. The center of reaction is moved as quickly as possible toward the center of the Earth, to keep things as spherically symmetric as possible and to minimize local stresses on the brittle crust. This phase lasts about eighteen months and covers about half a light-year, which is hardly enough to produce visible progress against the stars. (The Sun fairly quickly shrinks to a relatively bright but no longer helpful star, so it’s obvious that we’ve gone away from it. But it’s not so obvious that we’ve gone toward anything else. Any mountain climber knows this feeling.) The amount of mass consumed can be calculated by using equations which Poul Anderson has conveniently assembled in the Appendix of his book cited in my Bibliography. (My reactionless drive is what he calls a “field drive.”) Calculations for the later phases of the trip also use the assumption that energy consumption in super-c is described by Figure 1 in much the same way as elapsed time. (Very briefly, the relativistic mass increase is proportional to an increase in kinetic energy, and that’s equal to the work done to produce it.) Roughly speaking, the mass and therefore the average surface gravity drop to about sixty-five percent of their starting values during the initial acceleration phase, and escape velocity (important in estimating rate of atmosphere loss) to eighty percent. These gravity figures are misleading, however, because of the acceleration effects I’ll get to shortly—the distortion of the effective field by the applied thrust is much more important than the decrease in the average field.

     2. Tunneling, a discontinuous jump (requiring negligible time and energy; the latter is also implicit in Figure 1) to 1.5 c, followed by post-tunneling acceleration to about a million times the speed of light. One assumed property of the Rao-Chang universe is that objects moving faster than light and those moving slower are mutually undetectable; thus, tunneling causes the stars to vanish, leaving an empty sky and feeling of isolation which may be psychologically damaging to people out on the surface. However, most survivors at this point will be spending most of their time underground. The darkness in the middle portions of the trip would alone be enough to eliminate natural photosynthesis on land and sea, totally disrupting the ecology and exterminating vast numbers of species. However, the field distortion effects get there first.

     This acceleration phase lasts eighteen months and covers about fifty thousand light-years. Mass and average surface gravity (remember the precautions under #1) drop to forty percent, and escape velocity to sixty-five percent. If these figures were steady and uniform over the surface of the Earth, and other atmospheric parameters such as exosphere temperature were close to their present values, the “characteristic time” for the loss of the atmosphere (the time to lose a bit more than sixty percent of the starting amount) would be on the order of a couple of centuries.

     3. Cruise in super-c, at constant speed of 106c, About 1.7 × 106 light-years must be covered (depending on whose estimate you use; such things still can’t be measured very precisely), for a duration of 1.7 years. (This could be shortened somewhat by using a higher cruise speed, at the expense of more difficult navigation; it probably isn’t worth it.) During this phase, the field distortion effects are absent, so conditions might seem, in this sense, a bit more “normal” than during the acceleration phases. However, the strength of gravity is only forty percent of what we’re used to, and the atmosphere has probably already become thin enough that it will be difficult, if not impossible, for people to go outside without protection. It will continue to be lost.

     4. Tunneling back to 2/3 c (the stars—the unfamiliar stars of M31—come back); and final deceleration, again at 0.5 g, lasting eighteen months. Mass and surface gravity are down to seventeen percent, escape velocity down to forty percent. This corresponds to a characteristic time for atmosphere escape of just a few days, so effectively all atmosphere not trapped in sealed containers will be lost by the end of the trip. The remaining solid shell of Earth is not more than about four hundred miles thick, which may be thin enough to pose a danger of explosion or collapse. It may have to be deliberately broken up into smaller pieces; or possibly maintaining spherical symmetry to the end isn’t the best way to do things. In any case, it’s pretty clear that we are not talking about transplanting our home to a new galaxy. Earth as we know and love it is dead by the end of the trip. It has served as a vehicle, but for new homes we must find new planets.

     Now that we have a general outline of the trip, we come to those most important effects produced by the distortion of the effective gravitational field. Perhaps the most immediately striking of these is to change the effective “up-down” direction. To a person standing on what had been a level plain (or floor or ocean), the appearance and feel of this is exactly as if the Earth were tilting under his feet. All over the Earth, the ground appears to slope downward to the south. The amount of tilt, and the strength of the effective field, vary with latitude. The table below shows these quantities for several latitudes, for an early quasi-equilibrium state with a steady acceleration of 0.5 g, a negligible fraction of the Earth’s mass used up, and the exhautless drive in operation.

     Tall buildings will fall when the tilt becomes steep enough, and landslides—even on formerly level ground—will be widespread. The steepness of tilt will increase continuously as mass is used up and the spherically symmetric true gravitational component becomes weaker. One of the first globally important consequences of this effective tilting will be a tendency for the oceans and most of the atmosphere to flow “downhill” and concentrate (to such extent as they aren’t blasted or blown away) at and near the South Pole. In an equilibrium state, sea level and layers of constant atmospheric density correspond to equipotential surfaces of the effective gravitational field—in fact, this may be taken as an operational definition of gravitational equipotentials. Normally these surfaces are (practically) spheres concentric with the Earth. For the distorted effective field, they are distorted and displaced southward, as shown for one sample case in Figure 2. (Figure 2 also shows arrows representing the strength and direction of the effective field at the points shown in the table.)

     Calculating the distorted equipotentials is a rather laborious and necessarily approximate process involving a good deal of numerical integration. I won’t show the details here, but I will briefly outline the method for anybody who’s interested. The first requisite is a graph showing how the true gravitational field strength varies with distance from the center of the Earth, both inside and outside. This can be obtained by integrating a graph of density versus distance. (The exact shape of this graph depends on whose book you read and how recently it was printed. For phenomena on as large a scale as I was dealing with, I felt reasonably justified in using a somewhat simplified version in general agreement with several sources but ignoring some of the fine local fluctuations.) The field strength function can then be integrated to find the true gravitational potential, and the radial component of the acceleration field can be similarly integrated to find the “potential” associated with the thrust. The sum of these is the effective potential; an equipotential is drawn simply (!) by calculating a number of points with the same potential and connecting them by a smooth curve.

     The particular equipotential shown in Figure 2 is at present sea level at the equator, but passes a couple of thousand kilometers underground at the North Pole and a couple of thousand above at the South. To estimate where the oceans wind up, I looked for the boundary of the equipotential which would just accommodate all the water in the oceans in the dome-like region between itself and the surface. This turns out to be, very roughly, at about latitude 73° south—essentially all the oceans gather there in what appears to an observer as a big circular puddle (some 2,500 miles across) with sloping shores and a maximum depth of some 300 km. (It’s questionable how well the Earth could support such a layer of water, or how it would adjust to it. We do know that the crust was warped appreciably by the weight of thick glaciers during ice ages.) Assuming these figures to be at least roughly correct, despite the problem just mentioned and the approximate nature of the calculation, this puts the Antarctic Puddle entirely south of all normally inhabited continents and major islands. This eliminates permanent flooding problems—but substitutes severe drought—for all populous areas. Temporary tidal-wave-like flooding is not eliminated. That water goes over anything in its way as it moves south. If the thrust is jumped immediately to its full value, the water will be so badly out of equilibrium that it will move fast and deep right away, and continue sloshing back and forth for some time thereafter. To eliminate such a “jerk,” and allow the water to redistribute itself by means of relatively slow and shallow currents, the thrust will have to be built up gradually.

     Most of the atmosphere will also gather in the far south, and since moving air means “wind,” some fairly unbelievable weather will accompany its migration. Once it has stabilized, its loss will make it impossible for unprotected people (or other air-breathing organisms) to survive on the surface in the north. This alone will destroy the surface ecology, and people going underground will have to gather and recycle air, as well as everything else. And their buildings had better be strong—when the atmospheric pressure gets low enough, those which are airtight but weak will explode, just as houses already do in tornados. Transportation will become a formidable problem. Air-breathing combustion engines won’t work in the north. Aircraft (except rockets) will fly only in the south, and their altimeters will have little directly to do with altitude. The air collecting around Antarctica escapes into space even faster than predicted by the average escape velocity figures because it’s gathering right where the effective gravity is weakest.

     All of these acceleration effects will change—generally for the worse—as time goes on and the true gravitational field weakens. Only in the extreme south will gravity actually invert (and there only very late in the trip), but everywhere the ground will tilt more and more steeply.

     There is one more acceleration effect that needs to be considered. The continents themselves rest on huge plates which are floating on the asthenosphere, a “plastic” layer of the mantle which, like glass, acts rigid under short-term stresses but flows under long-sustained ones. (See Continents Adrift, in the Bibliography.) Given time, presumably the asthenosphere would also like to flow south, carrying continental masses with it and quite possibly tilting, bending, buckling, bumping, and fracturing them in the process. Normally the flow is appreciable only over a geological time scale (though it may be speeded up somewhat when the Earth is being heated predominantly from inside), so I would not expect actual movement of this sort to be a major problem in a trip lasting few years or likely even a few centuries. However, the stresses built up by a 0.5 g acceleration may produce local buckling and such which, though minor on a global scale, would be unnecessarily catastrophic as far as the passengers are concerned.

     Some of the effects of the 0.5 g acceleration considered so far are so drastic, and the time available to cope with them is so short, that it might be preferable to use a much lower acceleration for at least part of the trip, despite the disadvantages that has.

     The main disadvantage, of course, is time. Assuming an acceleration of 0.01 g, and the same critical speeds as before, the time scale is increased, not quite by a factor of fifty, but almost that. The initial acceleration phase lasts seventy-five years and covers some twenty-five light-years—enough to produce easily noticeable but generally not drastic changes in constellations. Mass and true-gravity figures are the same for the high-acceleration case, but more meaningful, since the field distortion is much less. Another century and a half are spent accelerating and decelerating in super-c—no constant velocity cruise phase is needed—and the final sub-c deceleration takes another seventy-five years. So altogether this trip lasts some three hundred years. Nobody who starts it finishes it—but maybe more of their descendants will.

     The major advantage of the low-acceleration method is that it’s gentler. Seismic disturbances, gravitational field distortion and its associated unpleasantries—all those things will be reduced. Physical stresses on the Earth, buildings, and inhabitants are all smaller, and so less (physical) damage should generally result. (Psychological damage may be another question.) The effective gravitational field changes very slightly—magnitudes differ from normal by an amount which is at first hardly perceptible (less than one percent); the “tilt” angle is initially less than one degree and even at journey’s end doesn’t exceed four degrees.

     Water and air still collect in the Southern Hemisphere, but the southern sea is larger, shallower, and more gradually varying in depth. I estimate the maximum (polar) depth to be about 30 km and the northern boundary to be at about 35° south latitude. (Which, unlike the high-acceleration case, does threaten to flood some populated areas—in particular, New Zealand and parts of South America and Australia.) The gentler equipotential slopes may leave enough atmosphere in middle and somewhat northerly latitudes to allow at least occasional surface exposure for a considerable while; travel will be easier and leaks less disastrous. The rate of atmospheric escape in the south is not nearly as bad as in the other model.

     In essence, this approach buys time. Ultimately, the Earth becomes uninhabitable either way, but this way the initial damage is not as high. There is more time when conditions are livable enough to make adjustments with reasonable ease. The price is that the trip takes a lot longer. With the high acceleration, conditions are more stringent, but a significant number of survivors may make planetfall in a few years. With the low acceleration, more people live out their natural lifespans, but none will live to finish the trip. There will be generations in the middle who never see a normal planet with a sun—even generations who never see a starry sky.

     Either way—or by any other variant such as an intermediate acceleration or a trip using several different accelerations—I think my original claim is not exaggerated: the trip would be arduous beyond anything in past human experience. In this article, I have dwelt on problems, not solutions. In fact, I have barely scratched the surface of the problems—I have mainly indicated the basic physical problems people will face if ever they should have occasion to attempt such an odyssey. I have only hinted at the overwhelming array of practical and human problems that would grow out of these. Things like: How do you provide enough life support equipment to enough people so that anybody gets there alive, particularly when you’re simultaneously facing an unprecedented wave of natural disasters at the very start? Even if you keep them alive, how do you keep them sane? If you use a high acceleration, what do you do about all the medical problems it causes—for example, in pregnant women and people with weak hearts? If you use a low acceleration, how do you make sure the trip is actually completed instead of becoming another lost-generation-ship-with-forgotten-mission story? How do you keep any semblance of civilization alive? If you somehow succeed in all these things, how do you insure that the totalitarianism that seems almost inevitable is temporary? How do you handle the logistics of getting the survivors off the Earth and onto a new world once they get there?

     And so on. And the inclusive question arises: Are all these problems too overwhelming? Would people actually have any chance at all of solving them?

     To this I can’t give a rigorously reasoned, experimentally verified answer. But I’ll venture a personal hunch: I think so. Not everybody; not by along shot. The ones who make it, if any do, will be tough and adaptable. But I suspect there are some folks around who have what it takes. I even have some ideas of how they might do it. But those are beyond the scope of this article. However, the thought has crossed my mind that therein lies a tale—and it’s called Lifeboat Earth.


     Poul Anderson, Is There Life On Other Worlds? New York, Collier (1963). (See especially pp. 190-201.)

     Stephen H. Dole, Habitable Planets for Man (Second Edition), New York, American Elsevier (1970). (See especially p. 12, pp. 36 ff.)

     Edwin F. Taylor and John Archibald Wheeler, Spacetime Physics, San Francisco, Freeman (1966). (See especially pp. 97-98.)

     J. Tuzo Wilson (Ed.), Continents Adrift (Readings from Scientific American), San Francisco, Freeman (1972).

From HOW TO MOVE THE EARTH by Stanley Schmidt (1976)

(ed note: Bussard Ramjet pilot Corbett was sent by The State totalitarian regime on an interstellar trip, but he goes his own way. Later he comes back to Terra after a relativistic trip lasting a few hundred millennia. He notices many small changes, such as the sun is burning hotter and Terra is now orbiting Jupiter. The State seems to have died out, replaced by two genetically engineered factions called the Boys and the Girls.)

      "Watch the show.”
     Certain stars glowed more brightly than others… and planetary systems circled them, greatly enlarged for effect. Now all but two of these systems turned sullen red—turned enemy. These were the worlds that had turned against the State.
     One of the red systems sparkled and faded into the background, its colony destroyed.
     The two neutral systems went red.
     Another system faded out.
     The view closed on Sol system… on more of Sol system than Corbell had known, with three dark gas giants beyond Pluto, and countless swarming comets.
      Fleets of spacecraft moved out toward the renegade colonies. Other fleets invaded. Sometimes they came like a hornet’s nest, many ships clustered around a Bussard ramjet core. Sometimes like a Portuguese man-of-war: thousands of ships as weights around the fringe of a great silver light-sail. Early fleets included hospital ships and return fuel; later there were massive suicide attacks.
     It went on for centuries. The State utopia became a subsistence civilization, turning all its surplus energy to war. The fleets moved at just less than lightspeed. News of success or failure or need for reinforcements moved barely faster. The State was Boys and Girls and dictators all united for the common good. Corbell hurt with the loss of that unity.

     He watched a beam of light bathe Sol system: laser cannon firing from Farside colony. Farside launched warships by light-sail at terrific accelerations. The ships dropped their sails and decelerated most of the way to Sol, arriving just behind the beam itself, long before the State could prepare. Corbell squirmed in his chair; he wanted to cry warning. For the State beat the invaders back, but failed to stop their hidden treachery.
     The war continued. Farside, economically ruined by its effort, fell before the counterattack. It took a man’s lifetime… too much time, before Astronomy noticed what the Farside traitors had done in the dark outside their dazzling light beam, in the distraction provided by the invasion.
     The State had looked for the light of fusion spacecraft, not the dim watery light of a new planet. The trans-Plutonian planet called Persephone had had a peculiar orbit, tilted nearly vertical to the plane of the solar system. Its new path had already taken it deep into the system.
     10 to the power 23 tons of hydrogen and hydrogen-compound ices were aimed to strike the sun at solar-escape velocity. Earth’s oceans would boil…

     The State did what it could. Tens of thousands of fusion bombs, Sol system’s entire armory, were set off at the dawn side of Persephone, just above the atmosphere. A thick rind of the planet’s atmosphere peeled away and streamed off like a comet’s tail, its mass pulling at Persephone’s dense core. A streamer of gas far more massive than the Earth broke free, and rounded the sun, and sprayed back toward the cometary halo.
     If the bombs could have been placed earlier, Persephone’s core would have done the same. It was rock and iron, yellow-hot, and it glowed X-ray hot as it streaked into the solar photosphere and disappeared.

     The sun grew bright.

     Oceans shrank, crops withered, tens of millions died before the State could place a disk of reflecting tinsel between Earth and Sol. It was a temporary measure. The sun’s new heat was permanent, at least on the human scale of time. Fusion would run faster in Sol’s hotter interior. The buried heat would leak to the photosphere and out.

     The State had one chance for survival. It could move the Earth by the method Farside had used to stop Persephone cold in its orbit.
     The State had had to abandon the Mercury mines: a serious industrial handicap. Nonetheless they were building something out there in the asteroid belt—something huge, like a starship big enough to carry the whole human race to safety. But no, that wasn’t it. Corbell was fascinated. He knew it might be the memory RNA, but he was fascinated anyway. He hardly heard what Skatholtz was saying: “It was sensible, Corbell. The Girls who made the light show ruled the sky. You are familiar with such things. Do you know now who hurled a moon at us?”
     “Not yet. Shut up and let me…”
     They had finished the thing. Two tubes, concentric, each a hundred miles long; the inner tube a mile wide, with thick walls of complex construction; the outer tube thinner and twice as wide. At one end, a bell-shaped rocket nozzle. At the other… Corbell knew more than he was seeing. Reworked military laser cannon, and vents, and a flared skirt, and thick stubby fins, there at the bottom end. Now temporary liquid hydrogen tanks were attached. Now the structure moved under its own power… it was a tremendous fusion motor… moving outward, circled by tiny ships… yeah.

     Corbell said, “How do you climb down off an elephant?”
     “Should I know that?”
     “You don’t climb down off an elephant. You climb down off a duck.” (1950s era grade-school joke. No, it wasn't funny back then either)
     “It’s so much safer. How do you move the Earth?
     Small wonder if the light show meant little to Skatholtz. Watching the construction of the motor—in the naked sunlight and sharp-edged, totally black shadows of space—was bewildering. The diagrams made sense to an architect, but they were only rotating lines to Skatholtz. But without bottled memory and without Corbell’s career in space, Skatholtz was still bright enough to makesome sense of what he was seeing.

     “You move something else,” Skatholtz said. “The damage done by the rocket’s thrust and by mistakes you might make will not kill anyone if nobody lives on the working body. Then the working body can be moved until the world falls toward it as a rock falls to the ground. What was the working body? Ganymede?”
     “Uranus. Can you stop the light show at that picture?”
     The lecture froze on an “artist’s conception”: a blurred, curved arc of Uranus’s upper atmosphere. The motor looked tiny floating there. Corbell said, “You see? It’s a double-walled tube, very strong under expansion shock. It floats vertical in the upper air. Vents at the bottom let in the air, which is hydrogen and methane and ammonia, hydrogen compounds, like the air that the sun burns. You fire laser cannon up along the axis of the motor, using a… color hydrogen won’t let through (light frequency that hydrogen absorbs). You get a fusion explosion along the axis.
     “I don’t understand all your words. Fusion?”
     “Fusion is the way a star burns. You probably used fusion bombs against the Girls.”
     “Okay. The hydrogen fusions in the middle of the motor—
     “—and the explosion goes out and up. It’s hottest along the axis, cooler when it reaches the walls of the motor. The whole mass blasts out the top, through the flared end. It has to have an exhaust velocity way higher than Uranus’s escape velocity. The motor goes smashing down into deeper air. You see there’s a kind of flared skirt at the bottom. The deep air builds up there at terrific pressure, stops the tube and blasts it back up. You fire it again.

     “Elegant,” said Skatholtz.
     “Yeah. Nobody’s there to get killed. Control systems in orbit. The atmosphere is fuel and shock absorber both—and the planet is mostly atmosphere. Even when it’s off the motor floats high for awhile, because it’s full of hot hydrogen compounds. If you let it cool off it sinks, of course, but you can bring it back up to high atmosphere by heating the tube with the laser, firing it almost to fusion. Start the light show again, will you?”
     Skatholtz barked something at Krayhayft. Corbell watched: Earth held out, barely. Heat-superconducting cables had to be run to the north polar cap to borrow its cold. The cap melted.
     Millions died anyway. No children were born; there wasn’t shelter for them. It took over a century to drop Uranus into place, six million miles ahead of the Earth in Earth’s orbit. The planet accelerated slowly, drawing Earth after it… and then sped up, to leave Earth behind, in a wider orbit. They lost the Moon.
     The sun expanded via its own internal heat. Light was reddened, but the greater surface lost more heat to space… to Earth. By now the Girls had charge of Uranus and the floating fusion motor. They moved the Earth again.
     Five times the Earth had to be moved. At one time it was circling precisely opposite Mars. Later, further out. Internally Sol’s fusion furnace had stabilized; but the photosphere was still growing. And the Earth must be moved a sixth time.

From A WORLD OUT OF TIME by Larry Niven (1976)

(ed note: the protagonist Louis Wu has been "hired" by an alien of the species Pierson Puppeteer to pilot a mission to a megastructure called a Ringworld. But first they have to stop at the Puppetter homeworld.)

     The pilot’s cabin was crowded. Louis hunched over the instrument panel, protecting buttons from the puppeteer’s careless hooves.
     “Spectroanalysis … yes. Now the blue-and-yellow double at two o’clock …
     “I have my bearings. Swing to 348, 72.”
     “What exactly am I looking for, Nessus? A cluster of fusion flames? No, you’d be using thrusters.”
     “You must use the scope. When you see it, you will know.”
     On the scope screen was a sprinkling of anonymous stars. Louis ran the magnification up until … “Five dots in a regular pentagon. Right?”
     “That is our destination.”
     “Good. Let me check the distance. — Tanj! (expletive. Acronym for There Ain't No Justice) That’s wrong, Nessus. They’re too far away.”
     No comment.
     “Well, they couldn’t be ships, even if the distance meter isn’t working. The puppeteer fleet must be moving at just under lightspeed. We’d see the motion.”
     Five dim stars, in a regular pentagon. They were a fifth of a light year distant and quite invisible to the naked eye. At present scope magnification they would have to be full sized planets. In the scope screen one was faintly less blue, faintly dimmer than the others.

     A Kemplerer rosette (sic. Should be Klemperer). How very odd.
     Take three or more equal masses. Set them at the points of an equilateral polygon and give them equal angular velocities about their center of mass.
     Then the figure has stable equilibrium. The orbits of the masses may be circular or elliptical. Another mass may occupy the center of mass of the figure, or the center of mass may be empty. It doesn’t matter. The figure is stable, like a pair of Trojan points.
     The difficulty is that there are several easy ways in which a mass can be captured by a Trojan point. (Consider the Trojan asteroids in Jupiter’s orbit.) But there is no easy way for five masses to fall accidentally into a Kemplerer rosette.

     “That’s wild,” Louis murmured. “Unique. Nobody’s ever found a Kemplerer rosette …” He let it trail off.
     Here between the stars, what could be lighting those objects?
     “Oh, no you don’t,” said Louis Wu. “You’ll never make me believe it. What kind of an idiot do you take me for?”
     “What is it that you will not believe?”
     “You know tanj well what I won’t believe!” (that the Puppeteers created the rosette)
     “As you please. That is our destination, Louis. If you will take us within range, a ship will be sent to match our velocity.”
     The rendezvous ship was a #3 hull, a cylinder with rounded ends and a flattened belly, painted shocking pink, and windowless. There were no engine apertures. The engines must be reactionless thrusters of the human type, or something more advanced.
     On Nessus’s orders Louis had let the other ship do the maneuvering. The Long Shot, on fusion drives alone, would have required months to match velocities with the puppeteer “fleet”. The puppeteer ship had done it in less than an hour, blinking into existence alongside the Long Shot with her access tube already reaching like a glass snake toward the Long Shot’s airlock.

     In the airlock the kzin stopped, suddenly caught by the sight of an expanding pentagon of stars.
     He could hardly have had a better view.
     The Long Shot, edging close in hyperdrive, had stopped half a light-hour ahead of the puppeteer “fleet”: something less than the average distance between Earth and Jupiter. But the “fleet” was moving at terrible speed, falling just behind its own light, so that the light which reached the Long Shot came from much further away. When the Long Shot stopped the rosette had been too small to see. It had been barely visible when Teela left the lock. Now it was impressively large, and growing at enormous speed.
     Five pale blue dots in a pentagon, spreading across the sky, growing, spreading …
     For a flashing instant there were five worlds around the Long Shot. Then they were gone, not fading but gone, their receding light reddened to invisibility.

     “Of course not,” said the puppeteer. “Doubtless you have been wondering about —”
     “Flying worlds,” the kzin interrupted.
     “And Kemplerer rosettes,” said Louis. “Okay, speak to us. Why flying worlds? Somehow it doesn’t seem safe to throw habitable worlds about with such gay abandon.
     “Oh, but it is, Louis!” The puppeteer was terribly earnest. “Much safer than this craft, for instance; and this craft is very safe compared to most human-designed craft. We have had much practice in the moving of worlds.
     “Practice! How did that happen?”
     “To explain this, I must speak of heat … and of population control. You will not be embarrassed or offended?”…

     …“But it does relate, Speaker. Half a trillion civilized beings produce a good deal of heat as a byproduct of their civilization. We had long since run out of farming land, and had been forced to terraform two worlds of our system for agriculture. For this it was necessary to move them closer to our sun.”
     “Your first experience in moving worlds. You used robot ships, of course.”
     “Of course … After that, food was not a problem. Living space was not a problem. We built high even then, and we like each other’s company.”…
     …“Our sole and only problem, at the time of which I speak, was heat.”
     “Heat is produced as a waste product of civilization.”
     “I fail to understand,” said Speaker-To-Animals.
     “An example. You would wish a light source at night, would you not, Speaker? Without a light source you must sleep, whether or not you have better things to do.”
     “This is elementary.”
     “Assume that your light source is perfect, that is, it gives off radiation only in the spectra visible to kzinti. Nonetheless, all light which does not escape through the window will be absorbed by walls and furniture. It will become randomized heat.
     “Another example. Earth produces too little natural fresh water for its eighteen billions. Salt water must be distilled through fusion. This produces heat. But our world, so much more crowded, would die in a day without the distilling plants.
     “A third example. Transportation involving changes in velocity always produces heat. Spacecraft filled with grain from the agricultural worlds produce heat on reentry and distribute it through our atmosphere. They produce more heat on takeoff.”
     “But cooling systems —”
     “Most kinds of cooling systems only pump heat around, and produce more heat for power.”
     “U-u-urr. I begin to understand. The more puppeteers, the more heat is produced.”
     “Do you understand, then, that the heat of our civilization was making our world uninhabitable?”

     “Incredible,” said Speaker-To-Animals. “Why didn’t you leave?”
     “Who would trust his life to the many deaths of space? Only such a one as me. Should we settle worlds with our insane?”…
     …They were of equal size: perhaps twice the angular diameter of the full Moon as seen from Earth. They formed a pentagram. Four of the worlds were circled by strings of tiny, glaring lights: orbital suns giving off artificial yellow-white sunlight. These four were alike in brightness and appearance: misty blue spheres, their continental outlines invisible at this distance. But the fifth …
     The fifth world had no orbital lights. It glowed by its own light, in patches the shapes of continents and the colors of sunlight. Between the patches was a black that matched the black of surrounding space; and this black, too, was filled with stars. The black of space seemed to encroach on continents of sunlight.
     “Incredible,” said Speaker-To-Animals. “I hardly dared believe it. You took your worlds with you.”
     “Puppeteers don’t trust spacecraft,” Louis said absently.…

     “But how?”
     “I had explained,” said Nessus, “that our civilization was dying in its own waste heat. Total conversion of energy had rid us of all waste products of civilization, save that one. We had no choice but to move our world outward from its primary.”
     “Was that not dangerous?”
     “Very. Then was much madness that year. For that reason it is famous in our history. But we had purchased a reactionless, inertialess drive from the Outsiders. You may guess their price. We are still paying in installments. We had moved two agricultural worlds; we had experimented with other, useless worlds of our system, using the Outsider drive. In any case, we did it. We moved our world.
     “In later millenia our numbers reached a full trillion. The dearth of natural sunlight had made it necessary to light our streets during the day, producing more heat. Our sun was misbehaving.
     “In short, we found that a sun was a liability rather than an asset. We moved our world to a tenth of a light year’s distance, keeping the primary only as an anchor. We needed the farming worlds and it would have been dangerous to let our world wander randomly through space. Otherwise we would not have needed a sun at all.”…
     …“Yes. Shortly after we finished moving our world, our sun began the process of expansion. Your fathers were still using the upper thigh bone of an antelope to crack skulls. When you began to wonder where our world was, you were searching the wrong orbits, about the wrong Suns.
     “We had brought suitable worlds from nearby systems, increasing our agricultural worlds to four and setting them in a Kemplerer rosette. It was necessary to move them all when the sun began to expand, and to supply them with sources of ultraviolet to compensate for the reddened radiation. You will understand that when the time came to abandon galaxy (when Beowulf Shaeffer discovered the galactic core was undergoing an explosion that would eventually sterilize the entire Milky Way), two hundred years ago, we were well prepared. We had had practice in moving worlds.”

From RINGWORLD by Larry Niven (1970)

      Runaway sun! Red, feeble, dying dwarf. Racing north­ward out of the constellation Ophiuchus, in mad flight from the Serpent and the Scorpion. Long ago christened "Barnard's Runaway Star," from its discoverer and its remarkable proper motion, it was the nearest star of the northern sky and the nearest found to have a habitable planet.
     "Please don't think I planned it, John! But the Medusae have tricked Eric—and the rest of us, it seems. They bargained to help us restore the Empire, in return for a shipload of iron. Now it seems they intend taking a good deal more."
     His gaunt frame shuddered.
     "They told me more of their history, just now, than Eric ever learned—and it's quite a history. They're old, John. Their sun is old. Their race was old, on that ghastly planet, before our Earth was ever born. They're too old, John—but they don't intend to die.
     "The remarkable motion of Barnard's Star, they tell me now, is a thing of their own accomplishment. Because the mineral resources of their own planet were used up long ago, they've arranged to visit others. In their career across the Galaxy, they live by looting the worlds they pass, and sometimes plant a colony—that's to be the fate of Earth, they tell me."
     He shook his white head with a sick, slow motion.
     "Please, John," he whispered, "don't think I ever intended that!"
     John Star and Jay Kalam stood voiceless with shock. The thing was unthinkable, but John Star knew it must be true. Reason insisted that the Medusae would scarcely join an interstellar war for a single cargo of iron. And Adam Ulnar's horrified remorse appeared sincere enough.
     Dazed, John Star pictured the doom of humanity. The System couldn't fight a science that built these black spider-ships of space and armed them with atomic suns for weapons; a science that fortified a planet with a belt of artificial satellites, and guided a star itself like a red corsair across the Galaxy.

From THE LEGION OF SPACE by Jack Williamson (1934)

Recently, we discussed science fiction stories about naturally occurring rogue worlds; there is, of course, another sort of wandering planet. That would be the deliberately-impelled variety, featured in stories in which ambitious travellers take an entire world along with them. This approach has many obvious advantages, not the least of which is that it greatly simplifies pre-flight packing. This spectacular notion has appealed to SF writers for nearly a hundred years; perhaps the first instance is to be found in Edmund Hamilton’s 1934 “Thundering Worlds,” in which every planet in the system is propelled across the interstellar gulf to escape a dying Sun. (As usual, if you know of an earlier publication, let us all know in the comments.)

Here are some further examples of the wandering world in print and/or film.

In Fritz Leiber’s The Wanderer (1964), the eponymous world-ship is a habitat as large and massive as the Earth, equipped with a faster-than-light drive whose appetite for fuel is as great as the ship itself . Unfortunately for humanity, the vessel is filled with trillions of beings (the ship uses not just its surface area, but its volume as living space) and those beings are self-centered enough to rip Earth’s Moon apart for fuel without worrying about what this catastrophe might do to the primitives of Earth. Cue a disaster spectacular filled with megadeaths and very sexy catgirls, neither of which was enough to prevent The Wanderer from being perhaps the second-worst novel ever to win a Hugo (IMHO, and in the opinion of many others; we can discuss in the comments).

I mention the novel largely in the hopes that someone will be inspired to revisit the plot. Even if their version isn’t all that good, odds are that it will at least be an improvement on the original.

Jerome Branch Corbell, protagonist of Larry Niven’s 1976 fix-up A World Out of Time, fled across gulfs of space and time at near light speeds in the hope that, by the time he returned to the Solar System, the authoritarian state of 2190 that resurrected him in a stranger’s body would have withered away. By the time he returns, three million years have passed. That is not long enough to explain the great changes in the Solar System. Not only has the Sun become a red giant billions of years ahead of schedule, the Earth now orbits a weirdly hot Jupiter. Someone has altered the Sun and someone—not necessarily the same person—has moved the planet; how and why account for large parts of the plot (though the overriding theme seems to be disco-era male anxieties about the War Between the Sexes).

Crawford Kilian’s 1989 standalone novel Gryphon depicts an Earth transformed, not necessarily for the better, by first contact. None of the advanced civilizations with which humanity is now in contact have constructed ships able to traverse and survive the vast gulfs of space that separate inhabited star systems. But these civilizations can communicate. Mere communication has upended life on Earth.

Worse is coming. One alien race is so fanatically devoted to spreading their faith that they have set their planet in motion. They don’t have a ship; they have a planet. They plan to convert the universe. Earth’s Solar System gains a new planet, and Earth must deal with some unpleasant neighbours.

The origins of the world-ships in Kameron Hurley’s 2017 The Stars Are Legion are unknown. What is clear is that the fleet of worlds is ancient and that the worlds are reaching the limits of their service lifetime. As world-ships fail, surviving craft fall on each other for necessary resources.

Zan wakes with no memory of her past, only assurances that she is in some mysterious way key to accessing the resources of the world-ship Mokshi for the people of Katazyrna. Perhaps she will save the Katazyrna. Perhaps she will be its doom.

Frant Gwo’s 2019 spectacular SF film The Wandering Earth (Chinese: 流浪地球, Pinyin: Liúlàng Dìqiú) is based on Liu Cixin’s 2000 novella of the same name. Faced with the Sun’s impending transformation into a red giant , the united Earth has strapped rockets onto our planet and launched itself on a thousand-year-plus journey, in a bid to save at least a remnant of humanity. A generation after setting out, the planet is approaching Jupiter for a necessary gravity assist. But as Jupiter grows ever larger in Earth’s sky, “gravitational spikes” knock out the vast Earth Engines propelling the planet. If the engines cannot be restarted, the billions who died in the name of the migration project will have sacrificed their lives in vain.

A curiosity noted while researching this essay: I can see no reason why this genre would be a male domain. Yet, save for the Hurley, all the examples I found were written by men. This must be due to some research failure on my part. Enjoy pointing out in comments all the books by women I should have mentioned.


  1. A special hat-tip to Donald Moffitt’s 1977 novel “The Jupiter Theft,” in which alien starships guzzle entire gas giants in their quest for fuel. Although the physics in the novel is, to put it kindly, somewhat confused, Moffitt populated his novel with some legitimately ingenious aliens. The only reason the book is relegated to a footnote rather than being in the main body of the essay is because while the aliens use up gas giants, and use entire moons as shielding, their living quarters are not themselves planets but more mundane (although still pretty impressive) habitats.
  2. Yeah, yeah, five billion years ahead of schedule. Accurate astronomy—science in general—is not always Mission One in stories of this sort. See Stanley Schmidt’s 1976 “The Sins of the Fathers,” also a contender for this essay if I’d reread it in the last forty years. Humanity’s great migration on a rocket-propelled Earth is triggered by the revelation that a chain reaction of supernovas is sweeping through the core of the Milky Way, not entirely unlike the supernova chain reaction in Larry Niven’s 1966 “At the Core.” Supernovas probably don’t work that way, although at least in the case of the Schmidt it’s less an undesirable natural phenomenon and more a Brobdingnagian industrial mishap.
  3. See Footnote 2 and square it. Movies place even less emphasis on getting the physics right than novels.




Stellar scale

Most stellar scale Megastructure proposals are designs to make use of the energy from a sun-like star while possibly still providing gravity or other attributes that would make it attractive for an advanced civilization.

  • The Alderson disk is a theoretical structure in the shape of a disk, where the outer radius is equivalent to the orbit of Mars or Jupiter and the thickness is several thousand miles. A civilization could live on either side, held by the gravity of the disk and still receive sunlight from a star bobbing up and down in the middle of the disk.
  • A Dyson sphere (also known as a Dyson Shell) refers to a structure or mass of orbiting objects that completely surrounds a star to make full use of its solar energy.
  • A Matrioshka brain is a collection of multiple Concentric Dyson Spheres which make use of different wavelengths of light.
  • A Stellar engine either uses the temperature difference between a star and interstellar space to extract energy or serves as a Shkadov thruster.
  • A Shkadov thruster accelerates an entire star through space by selectively reflecting or absorbing light on one side of it.
  • Topopolis (also known as Cosmic Spaghetti) is a large tube that rotates to provide artificial gravity.

Planetary scale

  • An Orbital is a space habitat similar to but much smaller than a Niven Ring. Instead of being centered on a star, it is orbiting a star, thus its diameter is typically on the order of magnitude of a planet. By giving a tilt to its orbit, there's a convenient day and night experience on its surface.
  • Globus Cassus is a hypothetical proposed project for the transformation of Planet Earth into a much bigger, hollow, artificial world with the ecosphere on its inner surface. This model serves as a tool to understand the World's real functioning processes.
  • Cloud Nine is Buckminster Fuller's proposal for a tensegrity sphere of size a mile in radius which would be large enough so that it would float in the sky if heated by only one degree above ambient temperature, creating habitats for mini cities of thousands of people in each "Cloud Nine".

Orbital structures

  • Orbital ring is an enclosed loop slightly larger than the circumference of the Earth so that it can maintain low earth orbit.
  • The Bernal sphere is a proposal for a space colony with a maximum diameter of 16 kilometers.
  • The Stanford torus is a different design with a diameter just under 1.7 kilometers.
  • The O'Neill cylinder is yet another space colony proposal.


Stellar scale

  • The Dyson shell (including its variation, the ringworld) has appeared in many works of fiction, including the Star Trek universe.
  • Larry Niven's series of novels beginning with Ringworld centered on, and originated the concept of a ringworld, or Niven ring. A ringworld is an artificial ring with a radius roughly equal to the radius of the Earth's orbit (1 AU). A star is present in the center and the ring spins to create g-forces, with inner walls to hold in the atmosphere. The structure is unstable, and required the author to include workarounds in subsequent novels set on it.
  • In the manga Blame! the Megastructure is a vast and chaotic complex of metal, concrete, stone, etc., that covers the Earth and assimilates the Moon, and eventually expands to encompass a volume greater than the orbit of Jupiter.
  • In White Light by William Barton and Michael Capobianco, a Topopolis is presented as taking over the entire universe.
  • In the Heechee books by Frederik Pohl the race of pure energy beings called The Foe have constructed the Kugelblitz, a black hole made of energy and not matter.
  • In the Xeelee series of books by Stephen Baxter, the eponymous alien race constructed the Ring, a megastructure made of cosmic strings, spanning over 10 million light years.
  • In Freelancer, The Dom'Kavosh's Dyson shell that is inhabited by a drone race created by the Dom'Kavosh, Nomads. This is reached via a hyper gate, created by the same creators as the Dyson sphere.
  • The Saga of Cuckoo series novel Wall Around a Star mentions a proposal to build a super dyson sphere, completely enclosing the Galactic Center.
  • The title of the novel Helix by Eric Brown directly references a stellar-scale helical megastructure. Different types of environments and habitats are interspersed along the structure, while their varying distance from the central star affects the climate.
  • The Quarg in the game Endless Sky are shown building a massive ring around one of their stars, which is most likely around one astronomical unit in diameter. A completed version of this can also be found in another location.
  • In Space Empires 4 and 5, the player can construct sphereworlds and ringworlds around stars.

Planetary scale

  • Several structures from the fictional Halo universe:
    • The original twelve Halos, seen in Halo: Cryptum, were 30,000 kilometers in diameter; a separate array of six Halos are 10,000 kilometers in diameter, with one of the original twelve later being reduced to this size in Halo: Primordium.
    • The Ark is a 127,530 km diameter structure from which the Halo Array can be activated and capable of building 10,000 km Halos. The "greater" Ark, seen in Cryptum and Primordium, is capable of producing 30,000 km Halos.
    • Onyx is an artificial planet made entirely out of Forerunner Sentinels (advanced replicating robots). At its core is a "shield world", contained within slipstream space, that is approximately one astronomical unit in diameter. The much smaller Shield World 0459, (approximately 1,400 km in diameter), is the setting for the latter half of Halo Wars. A third shield world, Requiem, is the primary setting for Halo 4. Requiem is an artificial hollow planet encased in a kind of Dyson Sphere.
    • High Charity, the Covenant's mobile planetoid station
  • Death Star from Star Wars
  • In Sonic Adventure 2 and Shadow The Hedgehog, the Eclipse Cannon is a WMD built inside of the Space Colony Ark. It fires a laser so strong that it can destroy planets and pierce stars. The Eclipse Cannon can't work on its own, and requires at least one Chaos Emerald for it to be functional. Even with only a few Chaos Emeralds powering it, it is still capable of destroying entire cities.
  • Buster Machine III from Gunbuster.
  • Culture Orbital
  • In the 2013 CGI anime movie, Space Pirate Captain Harlock, the Jovian Accelerator is an ancient, Death Star-like Weapon of mass destruction that uses energy from Jupiter's atmosphere to create a large beam of intense light strong enough to destroy an entire planet.
  • Trantor, the capital of an interstellar empire in Isaac Asimov's Foundation series, is an ecumenopolis, a planet entirely covered in one huge metal clad building, with only one small green space: the Emperor's palace grounds.
  • Coruscant, capital city in the Star Wars universe, entirely covers its host planet. It serves as capital of first the Republic and then later the First Galactic Empire.
  • The Galaxy Gun from the Star Wars universe, a large space station designed to destroy entire planets from across the galaxy could be considered a megastructure because its size is more than seven kilometers long.
  • The Centerpoint Station, from the Star Wars universe, a 350 km spherical space station at the Lagrangian point between the planets Talus and Tralus in the Corellia system. It was a gigantic and ancient hyperspace tractor beam with which an ancient race, known as Celestials, created the Corellia star system. With the help of the tractor beam whole planets could be moved through hyperspace and arranged into their actual orbits acound the central star. On the other hand, the same technology could be used as weapon to destroy even stars. On the inside of the main sphere a huge living space called Hollowtown was home to many people in similar fashion as on the inside of a dyson sphere.
  • The Ori Supergate seen in a number of episodes of Stargate SG1 could be classed as a megastructure
  • In The Hitchhiker's Guide to the Galaxy series, Earth, as well as other planets, were artificial megastructures. Earth was intended to function as a gigantic computer, and was built by a race of beings who made their living by manufacturing other planets.
  • The Star Forge from Star Wars: Knights of the Old Republic
  • Mata-Nui in the BIONICLE franchise is classifiable as a megastructre. In the story he is a massive robot as tall as a planet, and inside his body, every inhabitant of the BIONICLE Universe (Matoran, Toa, etc.) all live, unaware that they live inside a massive, space-traveling entity.
  • In the Robotech Sentinels novels, Haydon IV is an artificially constructed cyber-planet with android citizens.
  • In the Invader Zim episode "Planet Jackers", two aliens surround the Earth with a fake sky in order to throw it into their sun.
  • Nightmare's fortress from Kirby: Right Back at Ya! can be classified as a megastructure because it's the size of a small planet.
  • In several works, Arthur C. Clarke writes about a colossal hollow tube, first described in Rendezvous with Rama (1973), and inhabited by different races.
  • The Citadel in the Mass Effect universe is an enormous space station constructed by an ancient race of machines called the Reapers millions of years before the games in the series. At the time of Mass Effect 2, its population is 13.2 million.
  • In the game Airforce Delta Strike a large Space Elevator called the Chiron Lift is used to send supplies out into outer space.
  • In the Warhammer 40,000 series, the Imperial Palace (site of the Golden Throne wherein the Emperor of Mankind is kept alive indefinitely) could be considered a megastructure. The palace is a complex of continent-wide structures with the Golden Throne being located in an area stretching across the whole of the Himalayan mountains.
  • In the film Elysium, a luxury space station (a Stanford Torus) called Elysium houses the wealthy population of the human species.

Megascale structures

Structures that might not be classified as "Megastructures" because they do not meet the requirements, but are indeed "Mega" sized structures/constructions.

Stellar scale

From the Wikipedia entry for MEGASTRUCTURE


     Robert Heinlein’s early story “Universe” has been imitated countless times by most of the writers in the business.
     The idea was this: Present-day physics poses a limit on the speed of an interstellar vehicle. The ships we send to distant stats will be on one-way journeys, at least at first. They will have to carry a complete ecology they couldn’t carry enough food and oxygen in tanks. Because they will take generations to complete their journeys, they must also carry a viable and complete society.
     Clearly we’re talking about quite a large ship, with a population in the hundreds at least: high enough to prevent genetic drift. Centrifugal force substitutes for gravity. We’re going to be doing a lot of that. We spin the ship on its axis, and put all the things that need full gravity at the outside, along the hull. Plant rooms, exercise rooms, et cetera. Things that don’t need gravity, like fuel and guidance instruments, we line along the axis. If our motors thrust through the same axis, we will have to build a lot of the machinery on tracks, because the aft wall will be the floor when the ship is under power
     The “Universe” ship is basic to a discussion of life in space. We’ll be talking about much larger structures, but they are designed to do the same things on a larger scale: to provide a place to live, with as much security and variety and pleasure as Earth itself offers-or more.

     The fourth method is to accelerate all the, way, making turnover at the midpoint and decelerating the rest of the way. This works fine. Over interstellar distances it would take an infinite fuel supply—and by God we may have it, in the Bussard ramjet. A Bussard ramlet would use an electromagnetic field to scoop up the interstellar hydrogen ahead of it—with an intake a thousand miles or more in diameter—compress it, and burn it as fuel for a fusion drive. Now the multi-generation ship would become unnecessary as relativity shortens our trip time: four years to the nearest star, twenty.ŕne years to the galactic hub, twenty-eight to Andromeda galaxy—all at one gravity acceleration.
     The Bussard ramjet looks unlikely. It’s another ultimate, like generated gravity. Is the interstellar medium sufficiently ionized for such finicky control? Maybe not. But it’s worth a try.
     Meanwhile; our first step to other worlds is the “Universe” ship-huge, spun for gravity, its population in the hundreds, its travel time in generations.


     But we don’t really need spindizzies or generated gravity to build flying cities. In fact, we don’t really need to fill out Heinlein’s “Universe” ship. The outer hull is all we need. Visualize a ship like this:
  1. Cut a strip of Los Angeles, say, ten miles long by a mile wide.
  2. Roll it in a hoop. Buildings and streets face inward.
  3. Roof it over with glass or something stronger.
  4. Transport it to space. (Actually we’ll build it in space.)
  5. Reaction motors, air and water recycling systems, and storage areas are in the basement, outward from the street level. So are the fuel tanks. Jettisoning an empty fuel tank is easy. We just cut it loose, and it falls into the universe.
  6. We’re using a low-thrust, high-efficiency drive: ion jets, perhaps. The axis of the city can be kept clear. A smaller ship can rise to the-axis for sightings before a course change; or we can set the control bridge atop a slender fin. A ten mile circumference makes the fin a mile and a half tall if the bridge is at the axis; but the strain on the structure would diminish approaching the axis.
     What would it be like aboard the Ring City? One gravity everywhere, except in the bridge. We may want to enlarge the bridge to accommodate a schoolroom; teaching physics would be easier in free fall.
     Otherwise it would be a lot like the Generation ship. The populace would be less likely to forget their destiny, as Heinlein’s people did. They can see the sky from anywhere in the city; and the only fixed stars are Sol and the target star.
     It would be like living anywhere, except that great attention must be paid to environmental quality. This can be taken for granted throughout this article. The more thoroughly we control our environment, the more dangerous it is to forget it.



The next step up in size is the hollow planetoid. I got my designs from a book of scientific speculation, Islands in Space, by Dandrige M. Cole and Donald W. Cox.

STEP ONE: Construct a giant solar mirror. Formed under zero gravity conditions, it need be nothing more than an Echo balloon sprayed with something to harden it, then cut in half and silvered on the inside. It would be fragile as a butterfly, and huge.

STEP TWO: Pick a planetoid. Ideally, we need an elongated chunk of nickel-iron, perhaps one mile in diameter and two miles long. (it must be nickle-iron. If planetoid is stony, it will just fly into gravel when you start it spinning)

STEP THREE: Bore a hole down the long axis.

STEP FOUR: Charge the hole with tanks of water. Plug the openings, and weld the plugs, using the solar mirror.

STEP FIVE: Set the planetoid spinning slowly on its axis. As it spins, bathe the entire mass in the concentrated sunlight from the solar mirror. Gradually the flying iron mountain would be heated to melting all over its surface. Then the heat would creep inward, until the object is almost entirely molten.

STEP SIX: The axis would be the last part to reach melting point. At that point the water tanks explode. The pressure blows the planetoid up into an iron balloon some ten miles in diameter and twenty miles long, if everybody has done their jobs right.

     The hollow world is now ready for tenants. Except that certain things have to be moved in: air, water, soil, living things. It should be possible to set up a closed ecology. Cole and Cox suggested setting up the solar mirror at one end and using it to reflect sunlight back and forth along the long axis. We might prefer to use fusion power, if we’ve got it.
     Naturally we spin the thing for gravity.
     Living in such an inside-out world would be odd in some respects. The whole landscape is overhead. Our sky is farms and houses and so forth. If we came to space to see the stars, we’ll have to go down into the basement.
     We get our choice of gravity and weather. Weather is easy. We give the asteroid a slight equatorial bulge, to get a circular central lake. We shade the endpoints of the asteroid from the sun, so that it’s always raining there, and the water runs downhill to the central lake. If we keep the gravity low enough, we should be able to fly with an appropriate set of muscle-powered wings; and the closer we get to the axis, the easier it becomes. (Of course, if we get too close the wax melts and the wings come apart…)


     Let’s back up a bit, to the Heinlein “Universe” ship. Why do we want to land it?
     If the “Universe” ship has survived long enough to reach its target star, it could probably survive indefinitely; and so can the nth-generation society it now carries. Why should their descendants live out their lives on a primitive Earthlike world? Perhaps they were born to better things.
     Let the “Universe” ship become their universe, then. They can mine new materials from the asteroids of the new system, and use them to enlarge the ship when necessary, or build new ships. They can loosen the population control laws. Change stars when convenient. Colonize space itself, and let the planets become mere way-stations. See the universe!
     The concept is called Macrolife. Macrolife is large, powered, self-sufficient environments capable of expanding or reproducing. Put a drive on the inside-outside asteroid bubble and it becomes a Macro life vehicle. The ring-shaped flying city can be extended indefinitely from the forward rim. Blish’s spindizzy cities were a step away from being Macrolife; but they were too dependent on planet based society.
     A Macrolife vehicle would have to carry its own mining tools and chemical laboratories, and God knows what else. We’d learn what else accidentally, by losing interstellar colony ships. At best a Macrolife vehicle would never be as safe as a planet, unless it was as big as a planet, and perhaps not then. But there are other values than safety. An airplane isn’t as safe as a house, but a house doesn’t go anywhere. Neither does a world.


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     What’s bigger than a Dyson sphere? Dan Alderson, designer of the Alderson Double Dyson Sphere, now brings you the Alderson Disc. The shape is that of a phonograph record, with a sun situated in the little hole. The radius is about that of the orbit of Mars or Jupiter. Thickness: a few thousand miles.
     Gravity is uniformly vertical to the surface (freshman physics again) except for edge effects.. Engineers do have to worry about edge effects; so we’ll build a thousand-mile wall around the inner well to keep the atmosphere from drifting into the sun. The outer edge will take care of itself.
     This thing is massive. It weighs far more than the sun. We ignore problems of structural strength. Please note that we can inhabit both sides of the structure.
     The sun will always be on the horizon, unless we bob it, which we do. (This time it is the sun that does the bobbing.) Now it is always dawn, or dusk, or night.
     The Disc would be a wonderful place to stage a Gothic or a swords-and-sorcery novel. The atmosphere is right, and there are real monsters. Consider: we can occupy only a part of the Disc the right distance from the sun. We might as well share the Disc and the cost of its construction with aliens from hotter or colder climes. Mercurians and Venusians nearer the sun, Martians out toward the rim, aliens from other stars living wherever it suits them best. Over the tens of thousands of years, mutations and adaptations would migrate across the sparsely settled borders. If civilization should fall, things could get eerie and interesting.


     Pat Gunkel has designed a structure analogous to the Ringworld. Imagine a hollow strand of macaroni six hundred million miles long and not particularly thick-say a mile in diameter. Join it in a loop around the sun.
     Pat calls it a topopolis. He points out that we could rotate the thing as in the illustration—getting gravity through centrifugal force—because of the lack of torsion effects. At six hundred million miles long and a mile wide, the curvature of the tube is negligible. We can set up a biosphere on the inner surface, with a sunlight tube down the axis and photoelectric power sources on the outside. So far, we’ve got something bigger than a world but smaller than a Ringworld.
     But we don’t have to be satisfied with one loop! We can go round and round the sun, as often as we like, as long as the strands don’t touch. Pat visualizes endless loops of rotating tube, shaped like a hell of a lot of spaghetti patted roughly into a hollow sphere with a star at the center (and now we call it an aegagropilous topopolis.) As the madhouse civilization that built it continued to expand, the coil would reach to other stars. With the interstellar links using power supplied by the inner coils, the tube city would expand through the galaxy. Eventually our aegagropilous galactotopopolis would look like all the stars in the heavens had been embedded in hair.


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From BIGGER THAN WORLDS by Larry Niven (1974)

Dyson Sphere



     Freeman Dyson’s original argument went as follows, approximately.
     No industrial society has ever reduced its need for power, except by collapsing. An intelligent optimist will expect his own society’s need for power to increase geometrically, and will make his plans accordingly. According to Dyson, it will not be an impossibly long time before our own civilization needs all the power generated by our sun. Every last erg of it. We will then have to enclose the sun so as to control all of its output.
     What we use to enclose the sun is problematic. Dyson was speaking of shells in the astronomical sense: solid or liquid, continuous or discontinuous, anything to interrupt the sum light so that it can be turned into power. One move might be to convert the mass of the solar system into as many little ten-by-twenty-mile hollow iron bubbles as will fit. The smaller we subdivide the mass of a planet, the more useful surface area we get. We put all the little asteroid bubbles in circular orbits at distances of about one Earth orbit from the sun, but differing enough that they won’t collide. It’s a gradual process. We start by converting the existing asteroids. When we run out, we convert Mars, Jupiter, Saturn, Uranus … and eventually, Earth.
     Now, aside from the fact that our need for power increases geometrically, our population also increases geometrically. If we didn’t need the power, we’d still need the room in those bubbles. Eventually we’ve blocked out all of the sunlight. From outside, from another star, such a system would be a great globe radiating enormous energy in the deep infrared.
     What some science fiction writers have been calling a Dyson sphere is something else: a hollow spherical shell, like a ping pong ball with a star in the middle. Mathematically at least, it is possible to build such a shell without leaving the solar system for materials. The planet Jupiter has a mass of 2 × 1030 grams, which is most of the mass of the solar system excluding the sun. Given massive transmutation of elements, we can convert Jupiter into a spherical shell 93 million miles in radius and maybe ten to twenty feet thick. If we don’t have transmutation, we can still do it, with a thinner shell. There are at least ten Earth masses of building material in the solar system, once we throw away the useless gasses.
     The surface area inside a Dyson sphere is about a billion times that of the Earth. Very few galactic civilizations in science fiction have included as many as a billion worlds. Here you’d have that much territory within walking distance, assuming you were immortal.
     Naturally we would have to set up a biosphere on the inner surface. We’d also need gravity generators. The gravitational attraction inside a uniform spherical shell is zero. The net pull would come from the sun, and everything would gradually drift upward into it.
     So. We spot gravity generators all over the shell, to hold down the air and the people and the buildings. “Down” is outward, toward the stars.
     We can control the temperature of any locality by varying the heat-retaining properties of the shell. In fact, we may want to enlarge the shell, to give us more room or to make the permanent noonday sun look smaller. All we need do is make the shell a better insulator: foam the material, for instance. If it holds heat too well, we may want to add radiator fins to the outside.
     Note that life is not necessarily pleasant in a Dyson sphere. We can’t see the stars. It is always noon. We can’t dig mines or basements. And if one of the gravity generators ever went out, the resulting disaster would make the end of the Earth look trivial by comparison.
     But if we need a Dyson sphere, and if it can be built, we’ll probably build it.
     Now, Dyson’s assumptions (expanding population, expanding need for power) may hold for any industrial society, human or not. If an astronomer were looking for inhabited stellar systems, he would be missing the point if he watched only the visible stars. The galaxy’s most advanced civilizations may be spherical shells about the size of the Earth’s orbit, radiating as much power as a Sol-type sun, but at about 1O angstroms wavelength—in the deep infrared…
     …assuming that the galaxy’s most advanced civilizations are protoplasmic. But beings whose chemistry is based on molten copper, say, would want a hotter environment. They might have evolved faster, in temperatures where chemistry and biochemistry would move far faster. There might be a lot more of them than of us. And their red-hot Dyson spheres would look deceptively like red giant or supergiant stars. One wonders.
     In The Wanderer, novelist Fritz Leiber suggested that most of the visible stars have already been surrounded by shells of worlds. We are watching old light, he suggested, light that was on its way to Earth before the industrial expansion of galactic civilization really hit its stride. Already we see some of the result: the opaque dust clouds astronomers find in the direction of the galactic core are not dust clouds, but walls of Dyson spheres blocking the stars within.


     I pointed out earlier that gravity generators look unlikely. We may never be able to build them at all. Do we really need to assume gravity generators on a Dyson sphere? There are at least two other solutions.
     We can spin the Dyson sphere. It still picks up all the energy of the sun as planned; but the atmosphere collects around the equator, and the rest is in vacuum. We would do better to reshape the structure like a canister of movie film; it gives us greater structural strength. And we wind up with a closed Ringworld.
     Or, we can live with the fact that we can’t have gravity. According to the suggestion of Dan Aiderson, Ph.D., we can built two concentric spherical shells, the inner shell transparent, the outer transparent or opaque, at our whim. The biosphere is between the two shells.
     It would be fun. We can build anything we like within the free fall environment. Buildings would be fragile as a butterfly. Left to themselves they would drift up against the inner shell, but a heavy thread would be enough to tether them against the sun’s puny gravity. The only question is, can humanity stand long periods of free fall?


      Mathematically at least, it is possible to build a really big Dyson sphere, with the. heart of a galaxy at its center. There probably aren’t enough planets to supply us with material. We would have to disassemble some of the star of the galactic arms. But we’ll be able to do it by the time we need to.
     We put the biosphere—on the outside this time. Surface. gravity is minute, but the atmospheric gradient is infinitesimal. Once again, we assume that it is possible for human beings to adapt to free fall. We live in free fall, above a surface area of tens of millions of light years, within an atmosphere that doesn’t thin out for scores of light years.
     Temperature control is easy: we vary the heat conductivity of the sphere to pick up and hold enough of the energy from the stars within. Though the radiating surface is great, the volume to hold heat is much greater. Immustrial power would come from photoreceptors inside the shell.
     Within this limitless universe of air we can build exceptionally large structures, Ringworld-sized and larger. We could even spin them for gravity. They would remain aloft for many times the lifespan of any known civilization before the gravity of the Core stars pulled them down to contact the surface.
     The Megasphere would be a pleasantly poetic place to live. From a flat Earth hanging in space, one could actually reach a nearby moon via a chariot drawn by swans, and stand a good chance of finding selenites there. There would be none of this nonsense about carrying bottles of air along.

From BIGGER THAN WORLDS by Larry Niven (1974)

      An impossible object appears at the fringes of our galaxy, looming out of unknown space at a sixth the speed of light. The size of a giant star, it seems incredibly solid, not gaseous, and cool as a planet. Yet it’s far too light to be a mass of any possible substance. Any really solid object of its size would be sucked into a black hole by its own gravitation. Baffled by its riddles, the galactic observers call it Cuckoo.

     It’s a Dyson sphere, designed for the science fiction trilogy I’m now writing with Fred Pohl. Outside such fiction, Dyson spheres still belong to theory, as did positrons and neutrinos not long ago. Yet there are exciting reasons to believe they should exist. Though no actual observations have been confirmed, they’re open for imaginative exploration.

     But the problems of building physically different environments does offer a stimulating mental challenge and a widened scope for all sorts of story development. The Dyson sphere that Fred and I have been designing for our new trilogy is I think the largest habitable world in all science fiction.

     Freeman Dyson is a mathematician at the Institute for Advanced Study. He has suggested that our neighbor civilizations might be observable in space as points of infrared radiation, because a really advanced people might be able to trap and use all the radiation shining in every direction from their sun, allowing only waste heat to escape.

     The simplest way of doing this would be to build all the metal of the planets into a swarm of sun-vaned spacecraft, moving in orbits that keep them spread in a cloud all around their sun. I have suggested this sort of thing in a novel called The Power of Blackness, but for the trilogy we wanted a solid wall around the star.

     (Larry Niven took one step in this direction with Ringworld. His invention is an immense metal ring spinning around a sun, so fast that its air and its inhabitants are held against the inner surface by centrifugal force. To make the ring, he requires a very remarkable metal.)

     Our own first problem was building material for the sphere. Most of the Universe is hydrogen. The heavy metals, formed only in supernova explosions, are relatively rare. At best, the stuff of any ordinary planetary system would be enough to make only a flimsy sphere.

     But ours was to be a sort of cosmic ark, constructed by the common effort of all the intelligent races of an ancient galaxy, designed to carry them to safety when the galactic core explodes. Materials for it could come from many thousands, or even millions of stellar systems. Iron and its sister metals, incidentally, ought to be relatively plentiful in such an old galaxy, much of it formed by natural supernovas but more of it artificial. Very stable elements, they would be logical waste products from the most sophisticaed fusion power generators. We can assume the technology not only to build such generators, but to fabricate the waste metal into extraordinary alloys.

     Even given such alloys, however, there are still grave engineering problems in placing a solid shell around a star. No possible metal would be rigid enough to support itself against the gravitation of the central sun, or even against the pull of its own mass. Though a hollow sphere might be rotated fast enough to support its equatorial zone with centrifugal force, its polar regions would fall in.

     The solution we found was to surround the star with several layers of ring-shaped tubes. The tubes themselves are stationary, but they contain a heavy, low-viscosity fluid flowing fast enough to create the centrifugal force required to support the tubes and the loads above them. One set of parallel tubes holds up the “equator” — which isn’t really moving — and other sets, tilted at suitable angles, support the regions near the “poles.”

     The tubes are also heat-engines, with the fluid driven by energy absorbed from the sun and flowing through generator stations which supply power to all the inhabited levels above. Master computers adjust the velocity of flow to fit the loads.

     Cuckoo is enormous. With a radius of 86 million miles — 200 times that of our sun — it’s 540 million miles in circumference. The surface area is vast almost beyond imagination — some 9 × 1016 square miles. Space enough for story action!

     Though light for its size — a high vacuum in the same space might weigh more — it’s heavy enough. The entire construction, including tubes and fluid, living quarters and control devices and surface armor, cargo and fuel and atmosphere, has some ten times the mass of the star inside, which in turn is heavier by half than our sun.

     The shell is equivalent in weight to a plate of solid steel more than two miles thick; with the open spaces between the several levels, its total thickness is some forty miles. Massively armored, with the supporting tubes arranged in multiple layers, it is well protected from accidental damage.

     With fifteen solar masses. Cuckoo has a surface gravity about one percent that of Earth. This is force enough to hold the atmosphere which has collected above the outside armor. Part of this is interstellar gas; most of it is waste oxygen and helium from nuclear power plants which use water for fuel — tanks for this fuel form vast seas on Cuckoo’s surface. This oxy-helium mix is breathably dense at the lower levels and a hundred times as deep as the air of Earth.

     The last link in the complex energy-chain from the inner star, carrying convective heat from the metal surface toward open space, the atmosphere of Cuckoo has its own awesome meteorology, with storm-clouds rising a thousand miles high.

     Launched out of its exploding home galaxy in search of new worlds, the sphere is not only a super-planet but a supership. An immense ramjet, it uses magnetic fields created by the flow in the centrifugal tubes to sweep up cosmic gas, which is drawn past the central sun, energized, and expelled behind.

     The propulsion system raised new engineering problems, the worst of them due to the fact that a star at the center of a massive hollow shell is in unstable equilibrium, so that any nudge would tend to tip it toward collision. We were able, however, to turn this dangerous instability into a means of propulsion. The solution here is to store the surplus water and centrifugal fluid in enormous tanks spaced about the sphere, with a system of pumps to empty or fill them as necessary to adjust the gravitational balances to keep the sun in place at the center of the moving globe.

     This pump system and other controls are hooked to a complex net of sensors inside the sphere and on orbital satellites, and to the master computers, which are entirely automatic robot devices equipped with failsafe defenses and elaborately protected against time, accident, and vandalism.

     The passengers of Cuckoo are less immune to time and change. As the sphere was completed, they left their home planets for their alloted spaces in the levels between the in-most layer of centrifugal tubes and the heavy outside armor. Most of them are still there, some still active, others surviving in various states of arrested animation.

     By now the sphere has been in flight for hundreds of millions or perhaps billions of years, the remnants of its exploded native galaxy lost in the cosmos behind. Some of the races that built it are extinct; many have forgotten their origins, evolving or degenerating into wholly different orders of life, often in conflict with one another.

     The outer surface was at first an endless plain of bare metal, but much of it is covered now with soil from accumulated cosmic dust and the industrial wastes dumped from the occupied levels. Plant life has evolved there, supported by the energy-flow from below through a process of thermosynthesis. These plants are often luminescent, so that vast landscapes glow with varied color. There’s animal life, adapted to the low gravity and to varied local conditions of light or darkness, heat or cold, wild storms or unending calm — with no rotation and no external sun. Cuckoo had no seasonal climatic change. Most of these beings evolved on the surface, but some are migrants from below. A few are human.

     Not, however, native to Cuckoo. Much fiction to the contrary, our human body can’t be a cosmic norm. There are arguments, of course, that the evolution of intelligence on every world would tend to follow parallel tracks, that the logic of change would demand our bipedal shape and our erect posture, elevating the eyes and the brain and freeing the hands for tool-making. But all those arguments are rationalizations, I suspect, which overlook the chance factors that have helped make us what we are.

     The human inhabitants of Cuckoo are descendants of specimens taken by a scouting ship from Cuckoo that touched Earth many thousand years ago. Escaping to the surface, they have evolved physique and culture to fit their new environment. Though still at a primitive level, they’ve learned to fly with crude leather-and-fabric wings.

     Though we’ve assumed technologies for interstellar flight for our own galactic cultures as well as for the builders of Cuckoo, we’ve tried to respect the velocity of light as a relativistic limit to the speed of any material thing. For a solution to the problems of communication, we call on Jeny Feinberg’s tachyon, the hypothetical subatomic particle whose minimum-energy velocity is infinite. Though nothing material can be sent by tachyon beam, holographic scanning of objects and even of living beings yields information that can be transmitted to produce instantaneous replicates — copies of an original that remains safe at home.

From DESIGNING A DYSON SPHERE by Jack Williamson (1976)




      I myself have dreamed up an intermediate step between Dyson spheres and planets. Build a ring 93 million miles in radius—one Earth orbit—which would make it 600 million miles long. If we have the mass of Jupiter to work with, and if we make it a million miles wide, we get a thickness of about a thousand meters. The Ringworld would thus be much sturdier than a Dyson sphere.
     There are other advantages. We can spin it for gravity. A rotation on Its axis of 770 miles/second would give the Ringworld one gravity outward. We wouldn’t even have to roof itover. Put walls a thousand miles high at each rim, aimed inward at the sun, and very little of the air will leak over the edges.
     Set up an inner ring of shadow squares—light orbiting structures to block out part of the sunlight—and we can have day-and-night cycles in whatever period we like. And we can see the stars, unlike the inhabitants of a Dyson sphere.
     The thing is roomy enough; three million times the area of the Earth. It will be some time before anyone complains of the crowding.
     As with most of these structures, our landscape is optional, a challenge to engineer and artist alike. A look at the outer surface of a Ringworld or Dyson sphere would be most instructive. Seas would show as bulges, mountains as dents. River beds and river deltas would be sculpted in; there would be no room for erosion on something as thin as a Ringworld or a Dyson sphere. Seas would be flat-bottomed—as we use only the top of a sea anyway—and small, with convoluted shorelines. Lots of beachfront. Mountains would exist only for scenery and recreation.
     A large meteor would be a disaster on such a structure. A hole in the floor of the Ringworld, if not plugged, would eventually let all the air out, and the pressure differential would cause storms the size of a world, making repairs difficult.

     The Ringworld concept is flexible. Consider:
  1. More than one Ringworld can circle a sun. Imagine many Ringworlds, noncoplanar, of slightly differing radii—or of widely differing radii, inhabited by very different intelligent races.
  2. We’d get seasons by bobbing the sun up and down. Actually the Ring would do the bobbing; the sun would stay put. (One Ring to a sun for this trick.)
  3. To build a Ringworld when all the planets in the system are colonized to the hilt (and, baby, we don’t need a Ringworld until it’s gotten that bad!) pro tem structures are needed. A structure the size of a world and the shape of a pie plate, with a huge rocket thruster underneath and a biosphere in the dish, might serve to house a planet’s population while the planet in question is being disassemb1ed. It circles the sun at 770 miles/second, firing outward to maintain its orbit. The depopulated planet becomes two more pie plates, and we wire them in an equilateral triangle and turn off the thrusters, evacuate more planets and start building the Ringworld.


     One final step to join two opposing life styles, the Macrolife tourist types and the sedentary types who prefer to restructure their home worlds.
     The Ringworld rotates at 770 miles/second. Given appropriate conducting surfaces, this rotation could set up enormous magnetic effects. These could be used to control the burning of the sun, to cause it to fire off a jet of gas along the Ringworld axis of rotation. The sun becomes its own rocket. The Ringworld follows, tethered by gravity.
     By the time we run Out of sun, the Ring is moving through space at Bussard ramjet velocities. We continue to use the magnetic effect to pinch the interstellar gas into a fusion flame, which now becomes our sun and our motive power.
     The Ringworld makes a problematical, vehicle. What’s it for? You can’t land the damn thing anywhere. A traveling Ringworld. is not useful as a tourist vehicle, anything you want to see, you can put on the Ringworld itself… unless it’s a lovely multiple star system like Beta Lyrae but you just can’t get that close on a flying Ringworld.
     A Ringworld in flight would be a bird of ill omen. It could only be fleeing some galaxy-wide disaster.
     Now, galaxies do explode. We have pictures of it happening. The probable explanation is a chain reaction of novae in the galactic core. Perhaps we should be maintaining a space watch for fleeing Ringworlds… except that we couldn’t do anything about it.

From BIGGER THAN WORLDS by Larry Niven (1974)

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