some cities—or, at any rate, towns—at least six of them. If they were built for human beings, they could each hold about fifty thousand people. We’ve called them Rome, Peking, Paris, Moscow, London, Tokyo. They are linked with highways and something that seems to be a rail system.
“There must be enough material for centuries of research in this frozen carcass of a world. We’ve four thousand square kilometers to explore, and only a few weeks to do it in. I wonder if we’ll ever learn the answer to the two mysteries that have been haunting me ever since we got inside: who were they, and what went wrong?”
The recording ended. On Earth and Moon, the members of the Rama Committee relaxed, then started to examine the maps and photographs spread in front of them. Though they had already studied these for many hours, Commander Norton’s voice added a dimension no pictures could convey. He had actually been there, had looked with his own eyes across this extraordinary inside-out world, during the brief moments while its age-long night had been illuminated by the flares. And he was the man who would lead any expedition to explore it.
“Dr. Perera, I believe you have some comments to make?”
Ambassador Bose wondered briefly if he should have given the floor first to Professor Davidson, as senior scientist and the only astronomer. But the old cosmologist still seemed to be in a mild state of shock, and was clearly out of his element. All his professional career he had looked upon the universe as an arena for the titanic impersonal forces of gravitation, magnetism, radiation; he had never believed that life played an important role in the scheme of things, and he regarded its appearance on Earth, Mars, and Jupiter as an accidental aberration.
But now there was proof that life not only existed outside the solar system, but also had scaled heights far beyond anything that man had achieved, or could hope to reach for centuries to come. Moreover, the discovery of Rama challenged another dogma that Davidson had preached for years. When pressed, he would reluctantly admit that life probably did exist in other star systems; but it was absurd, he had always maintained, to imagine that it could ever cross the interstellar gulfs.
Perhaps the Ramans had indeed failed, if Commander Norton was correct in believing that their world was now a tomb. But at least they had attempted the feat, on a scale that indicated a high confidence in the outcome. If such a thing had happened once, it must surely have happened many times in this galaxy of a hundred billion suns. And someone, somewhere, would eventually succeed.
This was the thesis that, without proof but with considerable arm-waving, Dr. Carlisle Perera had been preaching for years. He was now a very happy man, though also a most frustrated one. Rama had spectacularly confirmed his views, but he could never set foot inside it, or even see it with his own eyes. If the devil had suddenly appeared and offered him the gift of instantaneous teleportation, he would have signed the contract without bothering to look at the small print.
“Yes, Mr. Ambassador, I think I have some information of interest. What we have here is undoubtedly a ‘space ark.’ It’s an old idea in the astronautical literature. I’ve been able to trace it back to the British physicist J. D. Bernal who proposed this method of interstellar colonization in a book published in 1929—yes, two hundred years ago! And the great Russian pioneer Tsiolkovsky put forward somewhat similar proposals even earlier.
“If you want to go from one star system to another, you have a number of choices. Assuming that the speed of light is an absolute limit—and that’s still not completely settled, despite anything you may have heard to the contrary” (there was an indignant sniff, but no formal protest, from Davidson)—“you can make a fast trip in a small vessel, or a slow journey in a giant one.
“There seems no technical reason why spacecraft cannot reach ninety per cent, or more, of the speed of light. That would mean a travel time of five to ten years between neighboring stare—tedious, perhaps, but not impracticable, especially for creatures whose life spans might be measured in centuries. One can imagine voyages of this duration carried out in ships not much larger than ours.
“But perhaps such speeds are impossible, with reasonable pay loads. Remember, you have to carry the fuel to slow down at the end