"Somehow that doesn't seem massive enough," he said. "Something that big should weigh as much as a good sized sun."
The kzin agreed. "One has the ludicrous picture of millions of beings trying to live on a construct no thicker than bookfilm."
"Your intuition is wrong," said the puppeteer with silver curls. "Consider the dimensions. If the ring were a ribbon of hullmetal, for example, it would be approximately fifty feet thick."
Fifty feet? That was hard to believe.
But Teela's eyes had been turned to the ceiling, and her lips had been moving silently but rapidly. "He's right," she said. "The math works out. But what's it for? Why would anyone build such a thing?"
"Room."
"Room?"
"Room to live," Louis amplified. "That's what it's all about. Six hundred trillion square miles of surface area is three million times the surface area of the Earth. It'd be like having three million worlds all mapped flat and joined edge to edge. Three million worlds within aircar distance. That'd solve any population problem.
"And what a problem they must have had! You don't go into a project like that one just for kicks."
"A point," said the kzin. "Chiron, have you searched neighboring stars for other, similar rings?"
"Yes, we -"
"And found none. As I thought. If the race that built the ring had known of faster-than-light travel, they would have settled other stars. They would not have needed the ring. Therefore there is only one ring."
"Yes."
"I am reassured. We are superior to the ringmakers in at least one respect." The kzin stood suddenly. "Are we to explore the habitable surface of the ring?"
"A physical landing might prove to be overambitious."
"Nonsense. We must inspect the vehicle you have prepared for us. Is its landing gear sufficiently versatile? When may we depart?"
Chiron whistled, a startled burst of discord. "You must be mad. Consider the power of those who built this ring! They make my own civilization seem savages!"
"Or cowards."
"Very well. You may go to inspect your craft when the one you call Nessus returns. For the time previous to that event, there are more data regarding the ring."
"You try my patience," said Speaker. But he sat down.
You liar, thought Louis. You take it well, and I'm proud of you. His own stomach was queasy as he returned to his couch. A baby blue ribbon stretched across the stars; and man had met superior beings — again.
The kzinti had been first.
When men first used fusion drives to cross the gaps between the stars, the kzinti were already using the gravity polarizer to power their interstellar warships. It made their ships faster and more maneuverable than human ships.
Man's resistance to the kzinti fleet would have been nominal, had it not been for the Kzinti Lesson: A reaction drive is a weapon devastating in direct proportion to it's efficiency as a drive.
Their first foray into human space had been a terrific shock to the kzinti. Human society had been peaceful for centuries, for so long that they had virtually forgotten war. But human interstellar ships used fusion-powered photon drives, launched by a combination of photon sail and asteroid-based laser cannon.
So the kzinti telepathe continued to report that the human worlds had no weapons at all … while giant laser cannon chopped at the kzinti ships, and smaller mobile cannon darted in and out on the light pressure of their own beams …
Slowed by unexpected human resistance and by the barrier of lightspeed, the war had run for decades instead of years. But the kzinti would have won eventually.
Except that an Outsider ship had stumbled across the small human colony on We Made It. They had sold the mayor the secret of the Outsider hyperdrive shunt, on credit. We Made It had not known of the kzinti war; but they learned of it fast enough when they had built a few faster-than-light ships.
Against hyperdrive the kzinti hadn't a prayer.
Later, the puppeteers had come to set up trading posts in human space …
Man had been very lucky. Three times he had met races technologically superior to him. The kzinti would have crushed him without the Outsider hyperdrive. The Outsiders, again, were clearly his superiors; but they wanted nothing that man could give them, except supply bases and information, and these they could buy. In any case the Outsiders, fragile beings of Helium II metabolism, were too vulnerable to heat and gravity to make good warriors. And the puppeteers, powerful beyond dreams, were too cowardly.
Who had built the Ringworld? And … were they warriors?
Months later, Louis was to see Speaker's lie as his personal turning point. He might have backed out then — on Teela's behalf, of course. The Ringworld was terrifying enough as an abstraction in numbers. To think of approaching it in a spacecraft, of landing on it …
But Louis had seen the kzin in terror of the puppeteers' flying worlds. Speakees lie was a magnificent act of courage. Could Louis show himself a coward now?
He sat down and turned to face the glowing projection; and as his eyes brushed Teela he silently cursed her for an idiot. Her face was alive with wonder and delight. She was as eager as the kzin pretended to be. Was she too stupid to be afraid?
There was an atmopshere on the ring's inner side. Spectroanalysis showed the air to be as thick as Earth's, and of approximately the same composition: definitely breathable to man and kzin and puppeteer. What kept it from blowing away was a thing to be guessed at. They would have to go and look.
In the system of the G2 sun there was nothing at all but the ring itself. No planets, no asteroids, no comets.
"They cleaned it out," said Louis. "They didn't want anything to hit the ring."
"Naturally," said the puppeteer with silver curls. "If something did strike the ring, it would strike at a minimum of 770 miles per second, the speed of rotation of the ring itself. No matter how strong the material of the ring, there would always be the danger of an object missing the outer surface and crossing the sun to strike the unprotected, inhabited inner surface."
The sun itself was a yellow dwarf somewhat cooler than Sol and a touch smaller. "We will need heat suits on the ring," said the kzin — rubbing it in, Louis thought.
"No," said Chiron. "The temperature of the inner surface is quite tolerable, to all of our species."
"How would you know that?"
"The frequency of the infrared radiation emitted by the outer surface -"
"You see me exposed as a fool."
"Not at all. We have been studying the ring since its discovery, while you have had a few eights of minutes. The infrared frequency indicates an average temperature of 290 degrees absolute, which of course applies to the inner as well as the outer surface of the ring. For you this will be some ten degrees warmer than optimum, Speaker-To-Animals. For Louis and Teela it is optimum.
"Do not let our attention to details mislead or frighten you," Chiron added. "We would not permit a landing unless the ring engineers themselves insisted. We merely wish you to be ready for any eventuality."
"You don't have any detail of surface formations?"
"Unfortunately, no. The resolving power of our instruments is insufficient."
"We can do some guessing," said Teela. "The thirty hour day-night cycle, for instance. Their original world must have turned that fast. Do you suppose that's their original system?"
"We assume that it is, since they apparently did not have hyperdrive," said Chiron. "But presumably they could have moved their world to another system, using our own technique."
"And should have," the kzin rumbled, "rather than destroy their own system in the course of building their ring. I think we will find their own system somewhere nearby, as denuded of worlds as this one. They would have used terraforming techniques to settle all of the worlds of their own system, before adapting this more desperate expedient."