A Time Odyssey Omnibus

by Arthur C Clarke - Stephen Baxter

  Eugene snapped, “Are you such a fool that you can’t see it?”

  Toby bit back, “Now look here—”

  Siobhan grabbed his arm. “Just take us through it, Eugene. Step by step.”

  Eugene visibly fought for patience. “Have you really no idea how unlikely this scenario is? Yes, there are rogue planets, formed independently of stars, or flung out of stellar systems. Yes, it may happen that such a planet could cross from one system to another. But it’s highly unlikely. The Galaxy is empty. To scale, the stars are like grains of sand, separated by kilometers. I estimate the chance of a planet like this coming anywhere near our solar system as being one in a hundred thousand.

  “And this Jovian didn’t just approach us—it didn’t just fall near the sun—it fell directly into the sun, on a trajectory that would take it directly toward the sun’s center of mass.” He laughed, disbelieving at their incomprehension. “The odds against such a thing are absurd. No naturalistic explanation is plausible.”

  Mikhail nodded. “Circumstantial, perhaps, but still… I’ve always thought Sherlock Holmes put it well. ‘When you have eliminated the impossible, whatever remains, however improbable, must be the truth.’”

  “Somebody did this,” Toby said slowly. “That’s what you’re saying. Somebody deliberately fired a planet, a big fat Jovian, straight at our sun. We’ve been hit by a bullet from God.”

  Bisesa said briskly, “Oh, I don’t think it has anything to do with God.” She stood up. “More coffee?”

  “Nicolaus—your target is the Vatican?” But the destruction would be much more extensive than that. A spaceplane returning from orbit packed a lot of kinetic energy: the Eternal City would be hit by an explosion with the force of a small nuclear weapon. She had not felt like crying before, but now tears pricked her eyes: not for herself, but for the destruction that would come. “Oh, Nicolaus. What a waste. What a terrible—”

  And then the bomb went off. It felt like a punch in the back.

  She was still conscious, for a while. She could even breathe. The cabin had survived, and its systems were doing its best to protect her. But she could feel herself tumbling, and monstrous G-forces pushed her deep into her seat. She could hear nothing; the blast had left her deafened—not that it mattered anymore.

  She was falling through the sky, she supposed, trapped in a piece of wreckage thrown out of a fireball high above Rome.

  Still she felt no anger, no fear. Only sadness that she would not see the greatest job of her life through to the end. Sadness that she had had no chance to say goodbye to those she loved.

  But she had been tired, she thought. So very tired. It was up to the others now.

  In the last second she felt a hand creep into hers. Nicolaus’s, a last, raw human contact. She gripped it hard. Then, as the spinning worsened, she blacked out, and knew no more.

  PART 4

  PERTURBATION

  26: ALTAIR

  The star called Altair is so far away that its light takes more than sixteen years to travel to Earth. And yet Altair is a neighbor, comparatively; only a few dozen stars lie closer to the sun.

  Altair is a stable star, but more massive than the sun. Its surface, twice the temperature of Sol’s, glows white with none of the sun’s hint of yellowness, and it breathes out ten times as much energy into the faces of its scattered flock of planets.

  Of those planets six are immense Jovians, all but one more massive than Jupiter. They all formed close to the parent star on looping orbits, wheeling like a flock of monstrous birds. But with time the Jovians, plucking at each other with their mighty gravitational fields, gradually migrated outward. Most of them settled into a neat clockwork array of circular orbits. Complex physical and chemical processes churned in the planets’ hot, deep interiors—and, in the tranquillity of eons, on some of those worlds life was spawned.

  One planet was different, though.

  This swollen monster, fifteen times more massive than Jupiter, was peculiarly unlucky in its interactions with its brethren. It was flung far out of the parent system, on a looping elliptical orbit whose farthest reach took it into the chill realm of comets. This huge orbit took millions of years to complete—and so every few megayears Altair’s huddled family of inner planets was disturbed by the rogue giant’s plummeting visits from the depths of space. Worlds that might have been Earths rolled and quivered, plucked by the rogue’s gravity. Not only that, but the rogue’s passage through Altair’s broad belts of comets and asteroids sent a heavy rain pouring into the inner system. On Altair’s worlds, dinosaur-killer impacts were the norm, falling a hundred times more frequently than on Earth.

  In time this process of destruction would have run its course. In the very long run the rogue Jovian would have destroyed the smaller worlds. Or it might have smashed into another Jovian: a catastrophe for both planets. Or, most likely, this moody wanderer would have become detached from the Altair system altogether, perhaps by the passage of another star, and it would have drifted away into sunless space alone.

  But there was an intervention.

  The most dramatic single event in the formation of the Earth was the mighty collision that shattered the proto-Earth into twin worlds, Earth and Moon. For a few days the glow of the wrecked world was bright enough to be seen over hundreds of light-years.

  Those who watched had eyes sensitive to colors for which there are no words in human languages. But they watched nevertheless: they watched everything and everywhere, patiently, indefatigably. And they noticed Earth’s violent birth.

  They watched what followed too: the gathering of oceans from comet water, a brief age of chemical churning, the startlingly rapid rise of simple life-forms, the more sluggish progress toward complexity, and at last a glimmer of intelligence. It was a familiar story in its broad thrust, only the details differing from world to world.

  But those who watched did not regard this as “progress.”

  In an ancient conclave, at levels of discourse no human mind could have comprehended—and despite some dissension—the gravest of decisions was made.

  And a weapon was selected.

  A sterilizing agent.

  How do you move a planet? There are many ways, but the method used at Altair was well within humanity’s understanding.

  It was that rogue Jovian’s very perturbability that made it so useful. Since the 1970s human engineers had been using gravitational “slingshots” to boost their spacecraft on their way. A spacecraft such as Voyager, say, could be “bounced” off Jupiter’s gravity well—and, like a Ping-Pong ball rebounding off the windshield of an eighteen-wheeler truck, if you got the angles right the spacecraft would be hurled away with hugely increased momentum. The space engineers had become expert at this technique, finding ways to use ever more elaborate chains of slingshots to tap into the solar system’s store of energy and momentum and so to reduce the amount of rocket fuel they needed to loft into space.

  Because Jupiter was some ten trillion trillion times as massive as Voyager, such encounters had not disturbed the target planet significantly. But if a world comparable in mass to Jupiter had followed Voyager’s trajectory, both incoming and target worlds would have been flung away in new directions.

  And here was the principle: to use gravitational slingshots to move worlds.

  A single impulse would be difficult to arrange, and wasteful, for much energy would have been dissipated in tidal distortions. But you could use a stream of asteroids to shift the much mightier mass of a planet without such undesirable consequences.

  And smaller rocks yet could be used to deflect the asteroids in the first place. A hierarchy of encounters could be arranged, with the tiniest of initial deflections—like a pebble thrown into a pond—causing a sequence of ever more immense disturbances. It helped that the mechanics of many-body gravitational systems were intrinsically chaotic and so sensitive to small disturbances.

  It would take planning, of course, to make this multiple cannon shot pa
y off. But it was only a question of orbital mechanics. It was efficient too, with very little energy wasted. To those to whom economy was a guiding principle, it was a method whose elegance appealed.

  The pebble was thrown.

  It took a thousand years for the cascade of interactions to shift the Jovian from its elongated orbit: no more would it trouble the tormented inner worlds of Altair. It would take another thousand years for the Jovian to cross the gulf of space from one stellar sand grain to the next. But that was of no concern. This was a long game.

  When it was done, attention was turned away. Those who had intervened would watch the dénouement; they believed that was their bleak duty. But there was time enough to be ready for that.

  On Earth, humans built ziggurats in veneration of their sun, which they still imagined to be a god. And yet their fate was already sealed. Or so those who had intervened believed.

  27: THE TIN LID

  Siobhan arranged to meet Bisesa in the London Ark, the old zoo in Regent’s Park.

  She had to drive down from Liverpool to do it. She had been up there to visit the new Eurasian Prime Minister in his Bunker, as everybody called it, a huge new underground governmental center implanted, controversially, in the massive concrete crypt of the grand old city’s Roman Catholic cathedral.

  Traveling down the M1, Siobhan hit her first roadblock as she passed St. Albans, still thirty kilometers or more from central London. The journey back had already taken eight hours. A couple of years ago, in a fast smart car with no upper speed limit, it might have taken three. But since then London had become a fortress.

  On this hot day in September 2041 a series of cordons had been put in place around the capital. The outermost fence was a barrier of roadblocks, wire fencing, and tank traps that ran from Portsmouth on the south coast, up through Reading and Watford, and past Chelmsford to the east coast. The Navy controlled access from the sea and the river just as tightly, and there were constant RAF patrols in the air overhead. Even at this first checkpoint it took Siobhan an hour to queue to have her ident chip, retinas, and vehicle chip scanned: she might still have the ear of a Prime Minister, but nobody got a free pass in these increasingly paranoid times.

  It had to be so. With seven months left before the storm, the problem of refugees from the smaller towns and the countryside was already significant. London had been Britain’s center of gravity since 1066, when the Norman Conqueror had exerted his brutal control over the old Saxon kingdom from his new Tower. Everybody knew that it would be to London, in the final days, that half the population of southern England would flee, as if drawn into a great drain. Hence the layers of barriers.

  As she waited, Siobhan saw a plume of thick black smoke rising above the city of St. Albans. Aristotle told her that it was the mark of a vast bonfire, the centerpiece of a ferociously wild party on the site of the long-erased Roman city of Verulamium. As time went on, most people continued to behave reasonably well, to the authorities’ general relief. But there were some who called themselves, gloomily, the Lords of the Last Days—and they sported and partied as if they believed it.

  The St. Albans fire was being burned in defiance of all environmental protection laws, of course, but there were plenty who no longer cared about that, not if everything was going to be fried in seven months’ time anyhow. The same thing was happening on a wider scale, as oil wells and gas fields were being pumped dry, and noxious substances pumped carelessly into the air and the seas.

  Frozen sleepers were another symptom of the lunatic fringe.

  Up in Liverpool she had delivered a report on the impact of the new craze in the United States for “hibernacula,”—huge underground vaults inside which the rich were having themselves cryogenically stored. These refugees from reality were seeking to skip over the sunstorm and escape into a better future. The hibernacula were becoming ever more popular despite medical advice that the freezing process probably wouldn’t work successfully—and nobody could guarantee an uninterrupted power supply through the sunstorm anyhow, so that the big day might result in an unfortunate defrosting. Besides, even if the system worked technically, where was the morality in escaping the present and leaving others to clean up the mess, then “returning” when the worst was over to reap the rewards? The “cryonauts” would surely not be welcomed, even in the most optimistic scenarios. And Siobhan had projected gloomily that if things went pear-shaped—if civilization fell apart despite the shield’s protection—the hibernacula would most likely serve the starving survivors as cellars of thawing meat…

  Such craziness captured media attention, but was fortunately still rare. And while these last days saw much foolishness and venality, there was some dignity too. More people were trying to save what they cherished than to smash things up in a final frenzy; projects such as the London Dome were flooded with volunteer workers. Many people were turning, predictably, to religion for solace, but few became fanatics of the kind who had killed Miriam Grec. Most prayed to their gods with quiet gravity, in the austere beauty of cathedrals, mosques, and temples, or simply in the privacy of their own hearts.

  Meanwhile the romantic poignancy of the end was evoking a flourishing of the arts, with literature, paintings, sculpture, and music of heartbreaking intensity being produced all over the world. It was a time for elegies.

  But many people, it seemed, faced the grimness of the future with a more private sadness. Populations worldwide were actually declining. There was a spate of suicides, but rather sadder was the news that birthrates were plummeting. This was not the time to bring a child into the world: indeed some religious leaders were arguing it might actually be sinful to procreate now, for a child who did not exist could not suffer.

  But those falling population numbers would make barely a dent before sunstorm day. Everything depended on the shield, as it always had.

  In September 2041, with only seven months left, the shield was as hair-raisingly behind schedule as ever, and yet it still progressed. Siobhan’s political masters in the Eurasian administration wanted endless facts, figures, Gantt charts to show progress achieved, critical-path diagrams to show bottlenecks and obstacles up ahead—and a few sexy photos of the staggering, Earth-sized structure growing in orbit.

  But nothing she said made any real difference, for there was nothing the pols could do differently, not now. Miriam Grec had got it right from the beginning. Her early intervention had given the project the worldwide political momentum it needed to begin. After Miriam herself had reaped the whirlwind, her successor, her deputy hastily installed into the top job, had been soundly beaten in the October 2040 poll by opponents who had run on a vaguely antishield ticket. But, just as Miriam had foreseen, once in office it was politically impossible for any Prime Minister to be the one who scrapped the shield. The logic had worked out just the same in the United States as in Eurasia.

  The new Prime Minister had not taken a shine to Siobhan, though. Siobhan was clearly still a key link in the communications and decision-making chain that led from the ground to orbit. But she was no longer among the favored inner few. That suited Siobhan fine. This was a time for getting on with the job, not for political arse kissing. And besides, the less she saw of the pols, the less chance there was of putting her foot in it.

  Beyond St. Albans, she worked her way through more roadblocks. At last, after some tricky inner-city driving, Siobhan reached the final barrier. This was the Camden Gate, one of ten great entrances set around the circumference of the Dome itself.

  As she queued she peered ahead curiously; she hadn’t come into the Dome from this direction before. The Gate, bright orange and peppered with searchlights and armed observation posts, rose like a Roman ruin above the mundanity of houses and shopping parades. And the smooth skin of the London Dome itself arced away into the washed-out blue of the sky beyond.

  The Dome was still incomplete, of course; the final enclosing panels would not be installed until the very last hours, so that the city would not have to s
urvive without light for too long. But still, even now, its immense skeletal form was startling. Siobhan couldn’t actually make out much of it, for she was too close to the horizon of this huge spherical cap. It was an odd shame that this greatest of all of Britain’s architectural achievements should be all but invisible from the ground: as the Aurora 1 crew had remarked ruefully of many Martian features, from close up it was simply too big to take in.

  But if you viewed it from the air, you could see what a magnificent structure the Dome was. Based on a near-perfect circle about nine kilometers in diameter, the Dome was centered on Trafalgar Square, but it covered the Tower of London at the eastern end of the old Roman city wall, and in the west it enveloped the West End, slicing through Hyde Park and just extending to include the Albert Memorial and the great South Kensington museums. In the north the Dome would shelter King’s Cross and Regent’s Park, where Siobhan was headed now, and to the south it reached across the river to the Elephant and Castle and beyond. Siobhan thought it was rather appropriate that the Dome would protect a stretch of the Thames itself, the river that had always been the city’s lifeblood.

  Every Londoner, with characteristically cheerful disrespect, called this great architectural triumph “the Tin Lid.”

  At last Siobhan was allowed to pass through the Gate. Signs admonished her to turn on her headlights.

  The view in the sudden twilight beneath the Dome’s roof was astounding. Supporting pillars rose up from the ground, like slim rainforest-canopy trees incongruously rising out of London’s mulch of town houses and flats, offices and cathedrals, ministries and palaces. Above, the sky was darkened by scaffolding and struts, made misty by distance. Helicopters and blimps flew just beneath the roof’s low curve. All this was lit by shafts of watery sunlight that passed through the breaks in the roof. The prospect had something of the feel of an immense antique ruin, perhaps, a place of pillars and graceful curves, the remnant of a vanished empire. But everywhere cranes rose up like skeletal dinosaurs, building, building. This was a glimpse, not of the past, but of the future.