‘The Southern Hemisphere looks quite different; for one thing, it has no stairways, and no flat central hub. Instead, there’s a huge spike – kilometres long – jutting along the axis, with six smaller ones around it. The whole arrangement is very odd, and we can’t imagine what it means.
‘The fifty-kilometre-long cylindrical section between the two bowls we’ve called the Central Plain. It may seem crazy to use the word “plain” to describe something so obviously curved, but we feel it’s justified. It will appear flat to us when we get down there – just as the interior of a bottle must seem flat to an ant crawling round inside it.
‘The most striking feature of the Central Plain is the ten-kilometre-wide dark band running completely round it at the halfway mark. It looks like ice, so we’ve christened it the Cylindrical Sea. Right out in the middle there’s a large oval island, about ten kilometres long and three wide, and covered with tall structures. Because it reminds us of Old Manhattan, we’ve called it New York. Yet I don’t think it’s a city; it seems more like an enormous factory or chemical processing plant.
‘But there are 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 kilometres 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 which 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 first given the floor 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 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 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 Professor Olaf 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 which 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 thousand million suns … and someone, somewhere, would eventually succeed.
This was the thesis which, without proof but with considerable arm-waving, Dr Carlisle Perera had been preach-ing 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 tele-portation, 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 colon-ization in a book published in 1929 – yes, two hundred years ago. And the great Russian pioneer Tsiolkovski 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 Professor 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 can-not reach ninety per cent, or more, of the speed of light. That would mean a travel time of five to ten years between neighbouring stars – 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 payloads; remember, you have to carry the fuel to slow down at the end of the voyage, even if you’re on a one-way trip. So it may make more sense to take your time – ten thousand, a hundred thousand years…
‘Bernal and others thought this could be done with mobile worldlets a few kilometres across, carrying thousands of passengers on journeys that would last for generations. Naturally, the system would have to be rigidly closed, recycling all food, air and other expendables. But, of course, that’s just how the Earth operates – on a slightly larger scale.
‘Some writers suggested that these Space Arks should be built in the form of concentric spheres; others proposed hollow, spinning cylinders so that centrifugal force could provide artificial gravity – exactly what we’ve found in Rama-‘
Professor Davidson could not tolerate this sloppy talk. ‘No such thing as centrifugal force. It’s an engineer’s phantom. There’s only inertia.’
‘You’re quite right, of course,’ admitted Perera, ‘though it might be hard to convince a man who’d just been slung off a carousel. But mathematical rigour seems unnecessary- ‘Hear, hear,’ interjected Dr Bose, with some exaspera-tion. ‘We all know what you mean, or think we do. Please don’t destroy our illusions.’
‘Well, I was merely pointing out that there’s nothing conceptually novel about Rama, though its size is startling. Men have imagined such things for two hundred years.
‘Now I’d like to address myself to another question. Exactly how long has Rama been travelling through space?
‘We now have a very precise determination of its orbit and its velocity. Assuming that it’s made no navigational changes, we can trace its position back for millions of years. We expected that it would be coming from the direction of a near-by star – but that isn’t the case at all.
‘It’s more than two hundred thousand years since Rama passed near any star, and that particular one turns out to be an irregular variable – about the most unsuitable sun you could imagine for an inhabited solar system. It has a brightness range of over fifty to one; any planets would be alternately baked and frozen every few years.’
‘A suggestion,’ put in Dr Price. ‘Perhaps that explains everything. Maybe this was once a normal sun and be-came unstable. That’s why the Ramans had to find a new one.’
Dr Perera admired the old archaeologist, so he let her down lightly. But what would she say, he wondered, if he started pointing out the instantly obvious in her own speciality…
‘We did consider that,’ he said gently. ‘But if our present theories of stellar evolution are correct, this star could never have been stable – could never have had life-bearing planets. So Rama has been cruising through space for at least two hundred thousand years, and perhaps for more than a million.
‘Now it’s cold and dark and apparently dead, and I think I know why. The Ramans may have had no choice – perhaps they were indeed fleeing from some disaster – but they miscalculated.
‘No closed ecology can be one hundred per cent efficient; there is always waste, loss – some degradation of the environment, and build-up of pollutants. It may take billions of years to poison and wear out a planet – but it will happen in the end. The oceans will dry up, the atmosphere will leak away…