Rama: The Omnibus

by Arthur C. Clarke

  It had changed, even in the last few minutes; a mist was rising from the Sea. For the first few hundred metres the ghostly white columns were tilted sharply forward in the direction of Rama's spin; then they started to dissolve in a swirl of turbulence, as the uprushing air tried to jettison its excess velocity. The Trade Winds of this cylindrical world were beginning to etch their patterns in its sky; the first tropical storm in unknown ages was about to break.

  CHAPTER 19

  A WARNING FROM MERCURY

  IT WAS THE FIRST time in weeks that every member of the Rama Committee had made himself available. Professor Solomons had emerged from the depths of the Pacific, where he had been studying mining operations along the mid-ocean trenches. And to nobody's surprise, Dr. Taylor had reappeared, now that there was at least a possibility that Rama held something more newsworthy than lifeless artifacts.

  The Chairman had fully expected Dr. Carlisle Perera to be even more dogmatically assertive than usual, now that his prediction of a Raman hurricane had been confirmed. To His Excellency's great surprise, Perera was remarkably subdued, and accepted the congratulations of his colleagues in a manner as near to embarrassment as he was ever likely to achieve.

  The exobiologist, in fact, was deeply mortified. The spectacular break-up of the Cylindrical Sea was a much more obvious phenomenon than the hurricane winds—yet he had completely overlooked it. To have remembered that hot air rises, but to have forgotten that hot ice contracts, was not an achievement of which he could be very proud. However, he would soon get over it, and revert to his normal Olympian self-confidence.

  When the Chairman offered him the floor, and asked what further climatic changes he expected, he was very careful to hedge his bets.

  'You must realize,' he explained, 'that the meteorology of a world as strange as Rama may have many other surprises. But if my calculations are correct, there will be no further storms, and conditions will soon be stable. There will be a slow temperature rise until perihelion—and beyond—but that won't concern us, as Endeavour will have had to leave long before then.'

  'So it should soon be safe to go back inside?'

  'Er—probably. We should certainly know in forty-eight hours.'

  'A return is imperative,' said the Ambassador for Mercury. 'We have to learn everything we possibly can about Rama. The situation has now changed completely.'

  'I think we know what you mean, but would you care to elaborate?'

  'Of course. Until now, we have assumed that Rama is lifeless—or at any rate uncontrolled. But we can no longer pretend that it is a derelict. Even if there are no life forms aboard, it may be directed by robot mechanisms, programmed to carry out some mission—perhaps one highly disadvantageous to us. Unpalatable though it may be, we must consider the question of self-defence.'

  There was a babble of protesting voices, and the Chairman had to hold up his hand to restore order.

  'Let His Excellency finish!' he pleaded. 'Whether we like the idea or not, it should be considered seriously.'

  'With all due respect to the Ambassador,' said Dr. Conrad Taylor in his most disrespectful voice, 'I think we can rule out as naive the fear of malevolent intervention. Creatures as advanced as the Ramans must have correspondingly developed morals. Otherwise, they would have destroyed themselves—as we nearly did in the twentieth century. I've made that quite clear in my new book Ethos and Cosmos. I hope you received your copy.'

  'Yes, thank you, though I'm afraid the pressure of other matters has not allowed me to read beyond the introduction. However, I'm familiar with the general thesis. We may have no malevolent intentions towards an ant-heap. But if we want to build a house on the same site…'

  'This is as bad as the Pandora Party! It's nothing less than interstellar xenophobia!'

  'Please, gentlemen! This is getting us nowhere. Mr. Ambassador, you still have the floor.'

  The Chairman glared across three hundred and eighty thousand kilometres of space at Conrad Taylor, who reluctantly subsided, like a volcano biding its time.

  'Thank you,' said the Ambassador for Mercury. 'The danger may be unlikely, but where the future of the human race is involved, we can take no chances. And, if I may say so, we Hermians may be particularly concerned. We may have more cause for alarm than anyone else.'

  Dr. Taylor snorted audibly, but was quelled by another glare from the Moon.

  'Why Mercury, more than any other planet?' asked the Chairman.

  'Look at the dynamics of the situation. Rama is already inside our orbit. It is only an assumption that it will go round the sun and head on out again into space. Suppose it carries out a braking manoeuvre? If it does so, this will be at perihelion, about thirty days from now. My scientists tell me that if the entire velocity change is carried out there, Rama will end up in a circular orbit only twenty-five million kilometres from the sun. From here, it could dominate the solar system.'

  For a long time nobody—not even Conrad Taylor—spoke a word. All the members of the Committee were marshalling their thoughts about those difficult people, the Hermians, so ably represented here by their Ambassador.

  To most people, Mercury was a fairly good approximation of Hell; at least, it would do until something worse came along. But the Hermians were proud of their bizarre planet, with its days longer than its years, its double sunrises and sunsets, its rivers of molten metal . . . By comparison, the Moon and Mars had been almost trivial challenges. Not until men landed on Venus (if they even did) would they encounter an environment more hostile than that of Mercury.

  And yet this world had turned out to be, in many ways, the key to the solar system. This seemed obvious in retrospect, but the Space Age had been almost a century old before the fact was realized. Now the Hermians never let anyone forget it.

  Long before men reached the planet, Mercury's abnormal density hinted at the heavy elements it contained; even so, its wealth was still a source of astonishment, and had postponed for a thousand years any fears that the key metals of human civilization would be exhausted. And these treasures were in the best possible place, where the power of the Sun was ten times greater than on frigid Earth.

  Unlimited energy—unlimited metal; that was Mercury. Its great magnetic launchers could catapult manufactured products to any point in the solar system. It could also export energy, in synthetic transuranium isotopes or pure radiation. It had even been proposed that Hermian lasers would one day thaw out gigantic Jupiter, but this idea had not been well received on the other worlds. A technology that could cook Jupiter had too many tempting possibilities for interplanetary blackmail.

  That such a concern had ever been expressed said a good deal about the general attitude towards the Hermians. They were respected for their toughness and engineering skills, and admired for the way in which they had conquered so fearsome a world. But they were not liked, and still less were they completely trusted.

  At the same time, it was possible to appreciate their point of view. The Hermians, it was often joked, sometimes behaved as if the Sun was their personal property. They were bound to it in an intimate love-hate relationship—as the Vikings had once been linked to the sea, the Nepalese to the Himalayas, the Eskimos to the Tundra. They would be most unhappy if something came between them and the natural force that dominated and controlled their lives.

  At last, the Chairman broke the long silence. He still remembered the sun of India, and shuddered to contemplate the sun of Mercury. So he took the Hermians very seriously indeed, even though he considered them uncouth technological barbarians.

  'I think there is some merit in your argument, Mr. Ambassador,' he said slowly. 'Have you any proposals?'

  'Yes, sir. Before we know what action to take, we must have the facts. We know the geography of Rama—if one can use that term—but we have no idea of its capabilities. And the key to the whole problem is this: does Rama have a propulsion system? Can it change orbit? I'd be very interested in Dr. Perera's views.'

  'I've given the subje
ct a good deal of thought,' answered the exobiologist. 'Of course, Rama must have been given its original impetus by some launching device, but that could have been an external booster. If it does have onboard propulsion, we've found no trace of it. Certainly there are no rocket exhausts, or anything similar, anywhere on the outer shell.'

  'They could be hidden.'

  'True, but there would seem little point in it. And where are the propellant tanks, the energy sources? The main hull is solid—we've checked that with seismic surveys. The cavities in the northern cap are all accounted for by the airlock systems.'

  'That leaves the southern end of Rama, which Commander Norton has been unable to reach, owing to that ten-kilometre-wide band of water. There are all sorts of curious mechanisms and structures up on the South Pole—you've seen the photographs. What they are is anybody's guess.'

  'But I'm reasonably sure of this. If Rama does have a propulsion system, it's something completely outside our present knowledge. In fact, it would have to be the fabulous "Space Drive" people have been talking about for two hundred years.'

  'You wouldn't rule that out?'

  'Certainly not. If we can prove that Rama has a Space Drive—even if we learn nothing about its mode of operation—that would be a major discovery. At least we'd know that such a thing is possible.'

  'What is a Space Drive?' asked the Ambassador for Earth, rather plaintively.

  'Any kind of propulsion system, Sir Robert, that doesn't work on the rocket principle. Anti-gravity—if it is possible—would do very nicely. At present, we don't know where to look for such a drive, and most scientists doubt if it exists.'

  'It doesn't,' Professor Davidson interjected. 'Newton settled that. You can't have action without reaction. Space Drives are nonsense. Take it from me.'

  'You may be right,' Perera replied with unusual blandness. 'But if Rama doesn't have a Space Drive, it has no drive at all. There's simply no room for a conventional propulsion system, with its enormous fuel tanks.'

  'It's hard to imagine a whole world being pushed around,' said Dennis Solomons. 'What would happen to the objects inside it? Everything would have to be bolted down. Most inconvenient.'

  'Well, the acceleration would probably be very low. The biggest problem would be the water in the Cylindrical Sea. How would you stop that from…'

  Perera's voice suddenly faded away, and his eyes glazed over. He seemed to be in the throes of an incipient epileptic fit, or even a heart attack. His colleagues looked at him in alarm; then he made a sudden recovery, banged his fist on the table and shouted: 'Of course! That explains everything! The southern cliff—now it makes sense!'

  'Not to me,' grumbled the Lunar Ambassador, speaking for all the diplomats present.

  'Look at this longitudinal cross-section of Rama,' Perera continued excitedly, unfolding his map. 'Have you got your copies? The Cylindrical Sea is enclosed between two cliffs, which completely circle the interior of Rama. The one on the north is only fifty metres high. The southern one, on the other hand, is almost half a kilometre high. Why the big difference? No one's been able to think of a sensible reason.'

  'But suppose Rama is able to propel itself—accelerating so that the northern end is forward. The water in the Sea would tend to move back; the level at the south would rise—perhaps hundreds of metres. Hence the cliff. Let's see…'

  Perera started scribbling furiously. After an astonishingly short time—it could not have been more than twenty seconds—he looked up in triumph. 'Knowing the height of those cliffs, we can calculate the maximum acceleration Rama can take. If it was more than two per cent of a gravity, the Sea would slosh over into the southern continent.'

  'A fiftieth of a gee? That's not very much.'

  'It is—for a mass of ten million megatons. And it's all you need for astronomical manoeuvring.'

  'Thank you very much, Dr. Perera,' said the Hermian Ambassador. 'You've given us a lot to think about. Mr. Chairman can we impress on Commander Norton the importance of looking at the South Polar region?'

  'He's doing his best. The Sea is the obstacle, of course. They're trying to build some kind of raft—so that they can at least reach New York.'

  'The South Pole may be even more important. Meanwhile, I am going to bring these matters to the attention of the General Assembly. Do I have your approval?'

  There were no objections, not even from Dr. Taylor. But just as the Committee members were about to switch out of circuit, Sir Lewis raised his hand.

  The old historian very seldom spoke; when he did, everyone listened.

  'Suppose we do find that Rama is—active—and has these capabilities. There is an old saying in military affairs that capability does not imply intention.'

  'How long should we wait to find what its intentions are?' asked the Hermian. 'When we discover them, it may be far too late.'

  'It is already too late. There is nothing we can do to affect Rama. Indeed, I doubt if there ever was.'

  'I do not admit that, Sir Lewis. There are many things we can do—if it proves necessary. But the time is desperately short. Rama is a cosmic egg, being warmed by the fires of the sun. It may hatch at any moment.'

  The Chairman of the Committee looked at the Ambassador for Mercury in frank astonishment. He bad seldom been so surprised in his diplomatic career. He would never have dreamed that a Hermian was capable of such a poetic flight of imagination.

  CHAPTER 20

  BOOK OF REVELATION

  WHEN ONE OF HIS crew called him 'Commander', or, worse still 'Mister Norton', there was always something serious afoot. He could not recall that Boris Rodrigo had ever before addressed him in such a fashion, so this must be doubly serious. Even in normal times, Lieut-Commander Rodrigo was a very grave and sober person.

  'What's the problem, Boris?' he asked when the cabin door closed behind them.

  'I'd like permission, Commander, to use Ship Priority for a direct message to Earth.'

  This was unusual, though not unprecedented. Routine signals went to the nearest planetary relay—at the moment, they were working through Mercury—and even though the transit time was only a matter of minutes, it was often five or six hours before a message arrived at the desk of the person for whom it was intended. Ninety-nine per cent of the time, that was quite good enough; but in an emergency more direct, and much more expensive, channels could be employed, at the captain's discretion.

  'You know, of course, that you have to give me a good reason. All our available bandwidth is already clogged with data transmissions. Is this a personal emergency?'

  'No, Commander. It is much more important than that. I want to send a message to the Mother Church.'

  Uh-uh, said Norton to himself. How do I handle this?

  'I'd be glad if you'll explain.'

  It was not mere curiosity that prompted Norton's request—though that was certainly present. If he gave Boris the priority he asked, he would have to justify his action.

  The calm, blue eyes stared into his. He had never known Boris to lose control, to be other than completely self-assured. All the Cosmo-Christers were like this; it was one of the benefits of their faith, and it helped to make them good spacemen. Sometimes, however, their unquestioning certainty was just a little annoying to those unfortunates who had not been vouchsafed the Revelation.

  'It concerns the purpose of Rama, Commander. I believe I have discovered it.'

  'Go on.'

  'Look at the situation. Here is a completely empty, lifeless world—yet it is suitable for human beings. It has water, and an atmosphere we can breathe. It comes from the remote depths of space, aimed precisely at the solar system—something quite incredible, if it was a matter of pure chance. And it appears not only new; it looks as if it has never been used.'

  We've all been through this dozens of times, Norton told himself. What could Boris add to it?

  'Our faith has told us to expect such a visitation though we do not know exactly what form it will take. The Bible gives hints. I
f this is not the Second Coming, it may be the Second Judgement; the story of Noah describes the first. I believe that Rama is a cosmic Ark, sent here to save those who are worthy of salvation.'

  There was silence for quite a while in the Captain's cabin. It was not that Norton was at a loss for words; rather, he could think of too many questions, but he was not sure which ones it would be tactful to ask.

  Finally he remarked, in as mild and noncommittal a voice as he could manage: 'That's a very interesting concept, and though I don't go along with your faith, it's a tantalizingly plausible one.' He was not being hypocritical or flattering; stripped of its religious overtones, Rodrigo's theory was at beast as convincing as half a dozen others he had heard. Suppose some catastrophe was about to befall the human race, and a benevolent higher intelligence knew all about it? That would explain everything, very neatly. However, there were still a few problems…

  'A couple of questions, Boris. Rama will be at perihelion in three weeks; then it will round the sun and leave the solar system just as fast as it came in. There's not much time for a Day of Judgement or for shipping across those who are, er, selected—however that's going to be done.'

  'Very true. So when it reaches perihelion, Rama will have to decelerate and go into a parking orbit—probably one with aphelion at Earth's orbit. There it might make another velocity change, and rendezvous with Earth.'

  This was disturbingly persuasive. If Rama wished to remain in the solar system it was going the right way about it. The most efficient way to slow down was to get as close to the sun as possible, and carry out the braking manoeuvre there. If there was any truth in Rodrigo's theory—or some variant of it—it would soon be put to the test.