Xeelee: Endurance

by Stephen Baxter

  The consequence of the Fist striking the Earth had been modelled for the Empress. The physics was simple, a function of the Fist’s immense kinetic energy; the consequence for the planet, modelled in a Virtual display, was dismaying. The impact, heralded by a tunnel of air shocked to superheated plasma, would be the source of a pulse of electromagnetic energy itself strong enough to sear anything alive across half a hemisphere – bright enough to pierce walls. The shock waves of air and water that would follow, and a hard rain of melted bedrock falling from the sky, would do the rest. Shira watched this over and over, obsessive.

  At the seventy-minute mark, the chamber door opened. Flood walked in. He was a bulky, strong-looking man, wearing a simple tunic and leggings. He carried a package, a sleek black box. Two others accompanied him, a man and a woman similarly dressed. These companions looked nervous, even overawed to be in this bunker under New York City itself, to be in the presence of an Empress. Flood, however, showed no fear.

  The Empress showed no reaction, watching her Virtual model go through its lethal sequence, over and over.

  Kale sneered. ‘So you are Flood of Alpha, once ambassador to this court, now the great rebel leader. And you dress like a farmer. How ostentatious. How predictable.’

  Flood smiled at him, and looked him up and down. ‘Nice jacket. Here. Hold this.’ He handed him the box he was carrying.

  Kale took it reflexively. Then, irritated, he passed it to Stillich. ‘What is it?’

  ‘Our final weapon. A nanotech modification of the smart plague – hardware, not software. Released, it would chew up the robust networks you were prudent enough to install – your optical-fibre links and all the rest. Necessarily delivered after landfall.’

  Stillich put this on the floor, gingerly. ‘Your final weapon save for the Fist.’

  ‘Save for that, yes.’

  ‘Why have you brought it here?’ the Admiral asked. ‘You have won. You have no need to do more damage.’

  Flood walked to the rim of the logic pool. ‘To put an end to that.’

  Now the Empress spoke, without looking up. ‘You are Flood.’

  He bowed. ‘Empress—’

  ‘Shira will do.’

  ‘Yes. Shira is your name. It always was, wasn’t it? I am here to discuss terms.’

  Stillich said tensely, ‘Keep it brief, farmer. We don’t have much time.’

  ‘Brief I can manage. Your Empress must stand down. This logic pool must be shut down – here, now, immediately, before my eyes. And we begin the establishment of a constitutional convention. A new relationship between the free worlds of all mankind.’

  ‘How civilised,’ Kale said. ‘A constitutional convention, or global obliteration.’

  ‘Admiral,’ Stillich snapped. ‘We don’t have the time. Flood – why the logic pool? This is at the centre of everything, isn’t it?’

  Flood faced Shira. ‘Our philosophers deduced this, the central truth of all she is doing. I myself was an observer, a spy in your court – even though I never saw your face before, ma’am.’

  ‘How little you understand,’ Shira said.

  ‘Oh, I think I understand well enough.’ Flood faced the Navy men. ‘You know her story by now. She is a refugee from the future – from a time that, even after a thousand years, is so far remote it remains the future. And she is going home the long way, year by year, heartbeat by heartbeat. But it isn’t the future she longs for – is it, Shira? You don’t want to be in this universe at all . . .’

  ‘None of this is real,’ Shira said, her voice a husk. ‘It is all transitory. We are simply forced to endure the motion of our consciousness along one of many chains of quantum functions, a sequence of potentiality to be collapsed, discarded, by the Ultimate Observer at timelike infinity. . .’

  Stillich tried to control his impatience. ‘This is just anachronistic philosophy. I don’t see what it is that she’s doing here that disturbs you, Flood.’

  ‘She longs for her Ultimate Observer. And she thought she could find her quantum messiah in mathematics . . .’

  The logic pool, he said, was a metamathematical universe. While not infinite it comprised more mathematical understanding, far more, than had yet been explored by mankind – and in principle, somewhere within the metamathematical branching of the pool, any algorithm possible might exist.

  Shira said softly, ‘All our science is based on the search for simple rules underlying complex phenomena. Simple algorithms can be shown to generate complexities, from the turbulent flow in a glass of water to the spiral structure of the Galaxy itself.’

  ‘You see the idea,’ Flood said. ‘There’s a lot of nonsense in there, but also a lot of treasure to be dug out. It’s as if you have a tank full of every possible combination of words in Earthish. Most of it is dross. But in there are the finest fruits of human scientific understanding – even those not discovered yet. But Shira has always been more ambitious than that, haven’t you, Empress?’

  Shira said, ‘The human consciousness is likewise the product of simple algorithms with particularly complicated outcomes. And similarly, any mind imaginable – human, post-human or alien – must be there to be discovered, in the pool, in metamathematical stasis.’

  Flood grimaced. ‘The Friends of Wigner were prepared to destroy Jupiter to send a message to the Ultimate Observer. Now this lunatic believes she can find the Observer in a tank of light.’

  ‘Show the Empress respect,’ Stillich said sharply.

  ‘But whether or not she ever achieved her goal, she is in danger of unleashing much greater threats on humanity. For some of the minds in there are not content with stasis, with waiting to be discovered. Look at this.’ He summoned up a Virtual of his own. ‘We’ve been tracking the consequences for years. Decades. We have our spies, in the Solar System. This is a neutrino scan we made from the Freestar just hours ago.’

  It took Stillich a moment to work out that he was looking at a cross section of the Earth, deep below the granite raft of Manhattan, and the imperial bunker. And down there, swimming in the mantle, was a shape, perhaps organic, perhaps artificial, a winged shape like a stingray, like a sycamore seed.

  ‘It isn’t fully formed,’ Flood said grimly. ‘Not fully operational. But it soon will be.’

  Kale asked, ‘What is it?’

  ‘In the Friends’ accounts of their dark future, there are hints of a race even more threatening to mankind than the occupiers of Earth from whom they fled. A race called—’ his pronunciation was uncertain, ‘Chee-lee, Zee-lee. They, or their potentialities, are lurking in the logic pool. And they are trying to break out.’

  ‘How?’ Kale snapped. ‘By constructing this ship, deep in the Earth? How are they doing that?’

  ‘We have no idea,’ Flood said. ‘Our only concern is to stop it, before this ship bursts from the Earth like a bird from its egg. This is a threat so potent it is trying to strike at us out of nothing more than of a statement of the logical possibility of its own existence. And if this thing gets out of the mantle, I don’t imagine our four light years’ separation would save Alpha System. Now do you see why it was necessary to wage this war? It wasn’t just for our freedom from Shira’s political domination. It was to free all mankind of this terrible threat – for Shira, your Empress from the future, was endangering all of us.’

  Stillich looked at the Admiral’s grim face.

  ‘Decision time,’ said Kale.

  ‘Yes, sir. My view? It’s not worth risking Earth to save this project of the Empress’s—’

  ‘The Project is worth any price,’ Shira murmured. ‘Even that.’

  But, Stillich thought, she seemed to be accepting defeat.

  Kale turned to her. ‘Ma’am – we have no time. We must accept his terms. We can discuss the details of your abdication later – the legitimisation of an interim government . . .’ He turned to Flo
od. ‘You have won, star-farmer.’

  Flood picked up the nanotechnological box and dropped it in the logic pool. It sank with barely a ripple, and then seemed to dissolve. Flood watched the pool, as the writhing metamathematical bifurcations withered, and the pale light began to die. ‘It is done.’

  Stillich said urgently, ‘Now call off your relativistic attack dog.’

  Flood smiled. ‘Done.’

  ‘None of this is real,’ Shira murmured. She rolled back into the shadows.

  Kale faced Flood. ‘You will pay for all you have done.’

  Flood gazed at him, his eyes full of regret. ‘Oh, I have paid, soldier. Believe me, I have paid.’

  And then the bunker shuddered, and a wave like a tide pulsed through Stillich’s gut.

  Kale staggered. ‘What was that?’

  When Stillich had recovered, he learned that Shira was gone.

  The Fist sailed through Sol’s asteroid belt.

  Earth was so close now that Densel Bel could see it, an image magnified and heavily corrected for relativistic distortions, suspended over his head – he could see the planet in real time, a blue marble, achingly beautiful, and yet scarred by war. And yet he could never touch it. The vast pulse of kinetic energy that had been injected into this ship by years of GUTdrive acceleration separated him from his home world just as much as if he had been stranded in another universe.

  Only subjective minutes remained before his life ended, and Earth died with him.

  Once more Flood appeared before him. ‘It’s over,’ he said, smiling.

  ‘What is?’

  ‘The war. Shira is abdicating – we are free. Now you must destroy the Fist Two.’

  ‘Me? Why me?’

  ‘This was your purpose all along, Densel Bel. You are my failsafe. I needed somebody on board who I knew would terminate the mission, even at the cost of his own life. And that’s you, a man loyal both to Earth, where you were born, and Footprint, where you have your family. You have the authority. Just say aloud, “Let it end”. The AI will do the rest. Goodbye, Densel Bel. I hope you feel the sacrifice you are making is worth it.’

  ‘Flood. Wait—’

  ‘Yes?’

  ‘Would you have done it? Would you have let the Fist strike the Earth?’

  ‘Oh, yes. To stop what Shira was doing – believe me, there was no choice. Good luck, Suber.’ He broke up into a cloud of pixels and disappeared.

  Suber. A lost name he’d used on a lost world. Densel Bel looked up at the blue Earth, and thought of Su-su and Fay. ‘Let it end.’

  Light flared, an instant of intense white pain—

  S-Day plus 7 months. Earthport.

  The flitter rose into the sky. The little cylindrical craft tumbled slowly as it climbed.

  Peering out from the rising flitter, Stillich had to admit that the Freestar, which he had come to inspect on behalf of Earth’s Navy, looked spectacular, with the newly constructed wormhole Interface, a bright blue tetrahedron with milky-gold faces, slung beneath its angular spine. When Flood and his crew returned to Alpha System in a couple of months, they would take the grudging good wishes of Earth’s interim government with them – and, more importantly, the business end of a new wormhole, which would link the worlds of Alpha and Sol for ever.

  ‘Or until the next political crisis,’ Flood said drily.

  ‘There is that,’ said Stillich.

  ‘Look – here comes another shipment of green muck from Titan.’

  A cargo pellet slung from Saturn’s moon had crossed the System unpowered, and now made an entry into Earth’s atmosphere, cutting a bright contrail across the blue sky. This crude shipment method was an interim emergency measure to keep Earth fed, until the great space elevators were hung in the sky once more.

  ‘Not “green muck”,’ Stillich said. ‘Algal concentrate.’

  Flood pulled a face. ‘Next time you visit Footprint, be my guest at dinner.’

  ‘That might be some time away,’ Stillich said gently.

  They both knew that was likely to be true. Too many had died, on Earth and elsewhere, for the populations of the Solar System to forgive their colonial cousins for the war, whatever the retrospective justification in terms of Shira’s murky crimes.

  But it would come, Stillich knew. Already Earth was recovering, as people and machines laboured to repair the damage done, and the vast resources of space were reattached to the damaged planet.

  ‘I saw your report on Shira’s escape,’ Flood said now. ‘You were serious in your conclusions?’

  ‘There’s no real doubt about it.’ Shira had stashed many treasures from her lost future down in that bunker, and among them was what appeared to be a transdimensional transport system: Shira had disappeared from the bunker by stepping sideways into one of the universe’s many extra compactified dimensions. ‘If that doesn’t qualify as a “hyperdrive” I don’t know what does.’

  Flood shook his head. ‘She had a hyperdrive. A faster-than-light transport system. And she kept it to herself all these centuries, while the rest of us limped across the Galaxy in sublight GUTships. Just so she had a last-resort escape hatch. How selfish.’

  ‘Maybe it’s just as well. Anyhow, I guess we know we are due to acquire the technology in a few centuries. Certainly it will transform the face of war.’ Stillich and Flood had both been key witnesses at an inter-governmental inquiry into the course and conduct of the war, an experience Stillich suspected had increased both their understandings. ‘When you think about it, an interstellar war fought out with sublight drives is right at the limit of the possible. For a start you would need a strong reason to do it; almost nothing is worth fighting such a campaign for.’

  Flood grunted. ‘You should read more history. Our fear of what Shira was up to was comparatively rational as a casus belli. Horrific wars have been fought over splinter-fine differences in ideologies. Look up the Crusades some time.’

  ‘But when we get an authentic first alien contact, rather than these dark hints and glimpses from the future . . . All of this might be remembered as mankind’s own last great civil war.’

  ‘The end of human war?’ Flood laughed. ‘I knew you were imaginative, Stillich. I didn’t have you down as a dreamer . . .’

  An alarm chimed, as the flitter prepared to dock with the Freestar. Stillich straightened his uniform, preparing for duty.

  So the humans emerged from their home System, optimistic, expansive.

  Then came Stillich’s ‘authentic’ first contact. And everything changed.

  REMEMBRANCE

  AD 5071

  ‘I am the Rememberer,’ said the old man. ‘The last in a line centuries long. This is what was passed on to me, by those who remembered before me.

  ‘The first Rememberer was called Harry Gage. He was ten years old when the Squeem came . . .’

  As he talked to some out-of-vision, flat-voiced cop inquisitor, Rhoda Voynet glanced around at her staff. Soldiers all, the planes of their faces bathed in golden Saturn light, they listened silently. The old man they saw before them, this ‘Rememberer’, was a Virtual, an image projected from a police station on Earth to this briefing room aboard the Jones, and the sunlight that shone on his face was much stronger than the diminished glow that reached this far orbit. Rhoda felt obscurely jealous of the warmth he felt.

  Prompted by his off-stage interrogator, the old man continued. ‘Harry Gage. He was born on Mars, in the Cydonia arcology. His great-grandparents were from Earth. There was a lot of that, in those days, before the Squeem. Everybody was mobile. Everything was opened up. Anything was possible.

  ‘Harry’s parents brought him to Earth, a once-in-a-lifetime trip to meet great-grandma and grandpa. He never did get to see them. They sure picked a bad day to call.’

  It had been the year 4874, nearly two centuries past. And Earth
was about to be conquered.

  The flitter bearing Harry Gage and his parents had tumbled out of the shimmering throat of the wormhole transit route from Mars to Earthport. As the flitter surged unhesitatingly through swarming traffic, Harry peered out of the cramped cabin, looking for Earth.

  From here, the home world was a swollen blue disc. Wormhole gates of all sizes drifted across the face of the planet, electric-blue sculptures of exotic negative-energy matter. Mum sat beside Harry, a bookslate on her lap, and Dad sat opposite, grinning at Harry’s reaction. Harry would always remember these moments well.

  The final hop to Earth itself took only a few hours.

  ‘Harry’s flitter landed in New York,’ the Rememberer said. ‘A spaceship coming down in the middle of Manhattan. Imagine that!’

  Harry and his parents emerged onto grass, a park, in the sunshine of a New York spring.

  Dad raised his face to the sun and breathed deeply. ‘Mmm. Cherry blossom and freshly cut grass. I love that smell.’

  Mum snorted. ‘We have cherry trees on Mars.’

  ‘Every human is allowed to be sentimental about a spring day in New York. It’s our birthright. Look at those clouds, Harry. Aren’t they beautiful?’

  Harry looked up. The sky was laced by high, fluffy, dark clouds, fat with water, unlike any on Mars.

  But Mum closed her eyes. She was used to the pyramids and caverns of Mars, and could not believe that a thin layer of blue air could protect her from the rigours of space.

  Harry was enchanted by Manhattan. He did not know then that most of what he saw was no more than decades old, painstakingly restored after the Starfall war. Nor could he know that little of it would be left standing mere hours from now. And as Harry peered up at the clouds he saw a line of light cut across the sky, scratched by a spark bright enough to cast faint shadows, even in the sunlight. He noticed New Yorkers looking up, vaguely concerned. This wasn’t normal, then. Even on Earth, even in New York.