(ed note: Luis Wu and company have been recruited by the Puppeteer species. They travel to the Puppeteer homeworld, and are startled to discover that it is a Klemperer Rosette.)
“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.…
“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.”