Introduction

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".

DEAD LIGHTS 1

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)
DEAD LIGHTS 2

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)

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.


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 alien installation created by forerunners which can grab passing spacecraft and crash them onto 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 abandonned 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.
THE SARGASSO OF SPACE

      "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)
SARGASSO TRAP

(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?"
     "Yes—but—"
     "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)
CALLING CAPTAIN FUTURE

      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)
HE FELL INTO A DARK HOLE

      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)

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.

DYSON TREE

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.

Arcology

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.

WIKIPEDIA: ARCOLOGY

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.

Development

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
TV TROPES: 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
Dictionary.com 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.

DOMED CITY

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.

Origin

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 sq.km 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
ROOFED MEGACITIES

      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)
INVULNERABLE DOME

      “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)
AEGIS

      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)
CITY FORCE FIELD

(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)
DIRTY

      "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)
DEAD CITY OF TANTOR

“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.

RESORT AND RETIREMENT AEROSTAT

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.

CITY OF APHRODITE

      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.

From LUCKY STARR AND THE OCEANS OF VENUS by Isaac Asimov (1954)

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"

RINGÉD PLANETS
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.
ECUMENOPOLIS
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.
MESKLIN
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.
ROCHEWORLD
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.
ULLER AND NIFLHEIM
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.
THE VIRGIN
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)
PLATEAU
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)
CANYON
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)
JINX
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)
THE SMOKE RING
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)
HABITABLE PLANETS AROUND PULSARS THEORETICALLY POSSIBLE

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 HABITABLE PLANETS AROUND PULSARS THEORETICALLY POSSIBLE
from Netherlands Institute for Radio Astronomy (2017)
HABITABLE NEUTRON STAR PLANET

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.

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
     *SPOILERS*
     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 WAR AGAINST THE RULL by A. E. van Vogt
     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.
DEATH WORLD

"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)

DEADLY FLORA AND FAUNA 1

(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)
DEADLY FLORA AND FAUNA 2

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)
TRENCO

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)
DEATHWORLD
      “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)
DUST RAG

(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.”
     "Why?”
     "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.

DEAD PLANET OF NEW PROVIDENCE

(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)
DEAD CITY OF TANTOR

“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.
BLACK WORLD

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)
BURNT OFF

(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)
NYARLATHOTEP

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 )
EASTER ISLAND

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
OZYMANDIAS1

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)
OZYMANDIAS2

(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.

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.

Please note that in our galaxy there are some real stars that are moving unusually fast.

Runaway stars are clipping along at around 100 kilometers per second. They are thought to be binary stars which passed too close to another star so one star got sling-shotted out. Or one star of a binary star system where the other blew up in a supernova. For science fictional purposes some sinister alien race converted their sun into a Shkadov thruster so they could go cruising for trouble.

A good example is 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. Jack Williamson used this in his novel The Legion of Space, home of the dreaded giant jellyfish-like Medusae who drive their solar system like a rocketship to invade innocent planets.

Hypervelocity stars on the other hand are screaming along like the proverbial bat-outta-hell. They move at about 1,000 km/s, which is quite a bit more than the galaxy's escape velocity. They are thought to have been sling-shotted by the Sagittarius A* supermassive black hole at the center of the galaxy. For science fictional purposes they are Shkadov thruster stars with the pedal to the metal, doing their best to get the heck outta Dodge ASAP. The important plot question being: what do they know that we don't? Apparently there is some awful thing that terrifies a civilization powerful enough to thrust their entire solar system up to a thousand klicks a second.

HOW TO MOVE THE EARTH

      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.

BIBLIOGRAPHY

     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)
A WORLD OUT OF TIME

(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)
     “Why?”
     “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)
PUPPETEER FLEET OF WORLDS

(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?”
     “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)
THE LEGION OF SPACE

      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)

Megastructures

MEGASTRUCTURE

Theoretical

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.

Fictional

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
BIGGER THAN WORLDS

THE MULTI-GENERATION SHIP


     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.

FLYING CITIES


     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.

INSIDE OUTSIDE

 

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…)

MACRO-LIFE


     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.

DYSON SPHERES

     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.

RINGWORLD 

      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.

DYSON SPHERES 2

     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?

ALDERSON DISC

     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.

COSMIC MACARONI

     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.

THE MEGASPHERE

     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.

TRAVELING RINGWORLDS

     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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