Xeelee: An Omnibus: Raft, Timelike Infinity, Flux, Ring

by Stephen Baxter

  Uvarov tilted his head, and the pod’s internal lights cast shadows across his imploded eye-sockets. ‘Tell me what you see,’ he hissed.

  ‘I see a neutron star,’ Mark said. ‘An unexceptional member of its species. Just ten miles across, but with a mass not much less than Sol’s . . . What has made this one unusual is the fact that it has a companion, which is - was - a normal star.’

  Before Mark, a Virtual diorama of the neutron star system glittered into existence; the globes of the neutron star and its companion were criss-crossed by lines of false colour, showing - Lieserl suspected - gravitational gradients, lines of magnetic flux, and other observables. Bits of text and subsidiary graphics drifted in the air beside the glowing objects.

  ‘Once,’ Mark said, ‘these stars were a binary pair - a spectacular one, since the neutron star must have been a brilliant giant. Somehow, the companion survived the giant’s supernova explosion. But the remnant of that explosion - the neutron star - is killing its companion, just the same.’ He pointed. ‘The neutron star’s gravity well is sucking out material from the companion . . . Look at it, Lieserl; those delicate-looking tendrils of smoke could swallow Jupiter. Some of the companion’s lost matter is falling onto the neutron star itself. And as the mass down there increases, the rotation of the neutron star will glitch - the neutron star must suffer starquakes, quite regularly. The rest of the gas is drifting off to form this ring we’re in, orbiting the neutron star.’

  ‘Do you think the birds caused the supernova explosion, Mark?’ Lieserl asked.

  He shook his head. ‘No. The system is too stable . . . I think the explosion took place long before the birds took an interest.’

  ‘And the companion?’

  He smiled, peering up at the complex sky. ‘Lieserl, that is one star the birds don’t need to kill. The neutron star is doing their work for them.’

  The Virtual representation of the neutron star expanded before his face, expelling the companion and the other features from the diorama. Mark peered in to a complex knot of light at what looked like one of the star’s magnetic poles.

  Lieserl looked away. The planet wasn’t far below, now; slowly it was turning from a ball of rock, suspended in emptiness, into a landscape - bare, bleak, riven by cracks.

  ‘What about the planets?’ Lieserl asked. ‘How could they have survived the supernova?’

  ‘My guess is they didn’t,’ Mark said, still staring at the star’s pole. ‘I think they probably formed after the explosion: coalesced from material in the gas ring, and from debris left over from the explosion itself - maybe from the previous planetary system, if there was one . . . Lieserl. Lethe. Look at this.’

  ‘What?’

  The neutron star Virtual representation swept across the cabin towards her; the little knot of light at the pole was thrust in her face. Lieserl flinched, but stared gamely into the glowing, complex image.

  Mark was grinning, his voice animated by excitement. ‘Do you see it?’

  ‘Yes, Mark,’ she said patiently, ‘but you’re going to have to tell me what I’m seeing.’

  ‘There’s a major disturbance in the gravitational gradients at that magnetic pole.’ Arrows clustered around the star’s pole, forming themselves into a two-dimensional plane. ‘Can you see it?’

  ‘What about it?’

  Mark sounded impatient. ‘Lieserl, I think there’s a sheet discontinuity down there. A two-dimensional defect. A domain wall, inside the star . . .’

  Lieserl frowned. ‘That’s impossible.’

  ‘Of course it is.’ He grinned. ‘How could a domain-wall defect form within the structure of a neutron star? Impossible . . . unless it’s been put there.’

  Uvarov’s ruined mouth stretched into a smile. ‘Put there?’

  ‘We wondered how come this neutron star was out here on its own - away from any galaxy, and moving so bloody fast. Well, now we know.’

  Lieserl found herself laughing. ‘This is outrageous. Are you suggesting—’ ‘Yes,’ he said seriously. ‘I think someone, maybe human, installed a discontinuity drive at the magnetic pole of this neutron star, and used it to hurl the whole system across space at close to lightspeed.’

  ‘But that’s absurd,’ she said. ‘Why should anyone do such a thing?’

  Now Uvarov laughed, at her. ‘Still the rationalist, Lieserl, after all our experiences? Well, perhaps we will soon learn the answer to such questions. But of this I’m sure - that it has some connection to this endless, bloody war in Heaven we’ve wandered into.’

  The pod’s descent bottomed out, now, and the little ship sailed over the planet’s battered landscape.

  At length, Mark said, ‘We’re over the source of the signals . . . There,’ he said suddenly. ‘Can you see it?’

  Uvarov tilted his head on its thin neck.

  Lieserl peered down.

  ‘A structure, Mark said. ‘There on the surface . . . Some kind of building. Come on; I’ll take us down.’

  I fell into the future, Spinner-of-Rope, through a network of transient wormholes that collapsed after me. My instruments were smashed, but I knew my lifedome must have been awash with high-energy particles and gravity waves. I was as helpless as a new-born babe.

  Poole sat in raw vacuum on the shoulder of the nightfighter with his legs tucked beneath him, lotus-style, his hands resting comfortably, palms-up, on his knees. Spinner could see a grooved pattern, moulded mundanely into the soles of his shoes.

  He said, I fell across five million years . . .

  Mark Wu - or rather, one of his Virtual consciousness foci, on the Northern - peered at the loop of cosmic string through the hundred eyes of the ship’s sensors. He wasn’t happy: his multifaceted view was muddy, imprecise.

  The trouble was, the ship was in orbit around this damn neutron star planet, which was falling through space so fast the observable Universe was relativity-shifted into a skinny, pale starbow. It was like being taken back to the Northern’s thousand-year flight. Mark had to deconvolve out the effects of the near-lightspeed motion: to unsmear the Universe back out of the starbow once more.

  Mark had subroutines to achieve this. But it was, he thought uneasily, a little like unscrambling an egg. The resulting images weren’t exactly clear.

  Inside his box of processors, Mark Wu worked on nanosecond timescales. He could process data at several millions of times the rate achievable by humans, and it sometimes took an effort of will to come back out of there and return to the glutinous slowness of the human world.

  It was seven centuries since his physical death and downloading into the AI banks of the Northern, and he’d steadily got more proficient at non-human operation. Right now, for instance, he was maintaining a conventional human-Virtual on the pod with Lieserl and Uvarov, and another with Louise in the Great Britain, in parallel with his direct interfacing with the Northern’s systems.

  Running these multiple consciousness foci felt odd, but he’d grown used to enduring minor discomforts when the need arose.

  And there was need now.

  Maybe he should have tried to veto this trip to the neutron star, he thought. It had brought the Northern close - too damn close - to this loop-cloud of cosmic string. When dealing with an object a thousand light-years across, he thought sourly, a separation of a mere handful of light-years didn’t seem nearly sufficient.

  Mark split off a series of more subordinate foci, and set to scanning overlapping sectors of the sky.

  His image of the Universe was a mosaic, constructed of the fragments supplied to him by the sensors; he imagined it was a little like looking out through the multi-faceted eyes of a fly. And the Universe was criss-crossed, everywhere, by string double-image paths - it was as if the sky were some huge dome of glass, he thought, marred by huge cracks.

  By studying the double images of stars and galaxies, Mark was able to check on the near-lightspeed velocities of the string segments; he constantly updated the internal model he maintained of the local strin
g dynamics, trying to ensure the ship stayed a safe distance away from—

  A watchful subroutine sounded an alarm. It felt to Mark like a prickling of vague unease, a shiver.

  . . . There was movement, in the field of view of one sensor bank. He swivelled his consciousness, fixing most of his attention on the anomaly picked up by that sensor bank.

  Against a background provided by a beautiful, blue-stained spiral galaxy, he saw a double track of multiple stellar images.

  There had to be two lengths of string there, he realized: two arcs of this single, huge loop of string, no more than light-hours apart. And he could see from the melting flow of the star images that the arcs were sliding past each other in opposite directions; maybe eventually they would intersect.

  In some places there were three images of single stars. Light from each of those stars was reaching him by three routes - to the left of the string pair, to their right, and straight through the middle of the strings.

  The cause of the alert was obvious. All along the double tracks, he saw, star images were sliding, as if slipping across melting spacetime. These strings must be close - maybe even within the two-light-year limit he’d imposed on himself as a rough safety margin.

  He ran a quick double-check on the routines he’d set up to monitor the strings’ distance from the ship. He wondered if he ought to tell Louise and Spinner about this . . .

  Now, suddenly, alarm routines shrieked warnings into his awareness. It was like being plunged into an instant panic; he felt as if adrenaline were flooding his system.

  What in Lethe—

  He interrogated his routines, briskly and concisely. It took only nanoseconds to figure out what was wrong.

  The pair of string arcs were closer than he’d thought at first. His distance-estimation routines had been thrown by the interaction of the two strings, by the way the pair jointly distorted star images.

  So the strings were closer than his monitoring systems had told him. The trouble was, he couldn’t tell how close; maybe they were a lot closer.

  Damn, damn. I should have anticipated this. Feverishly he set off a reprogramming routine, ensuring that for the future he wouldn’t be fooled by multiple images from pairs of string lengths like this - or, indeed, from any combination.

  But that wasn’t going to help now.

  He ran through a quick hack procedure, trying to get a first-cut estimate of the strings’ true distance . . .

  He didn’t believe the answer. He modified the procedure and ran it again.

  The answer didn’t change.

  Well, so much for my two-light-year safety zone.

  The string pair was only around ten million miles from the Northern - less than a light-minute.

  One of the pair of strings was receding - but the other was heading straight for the ship.

  He ran more checks. There was no error.

  In fifty seconds, that encroaching string would hit the Northern.

  He burst out of the machinery and back into the world of humans. With impatience he waited for pixels to congeal out of the air, for his face to reassemble; he felt his awareness slow down to the crawl of humans.

  29

  Five million years after the first conflict between humans and Qax, the wreckage of a Spline warship had emerged, tumbling, from the mouth of a wormhole that blazed with gravitational radiation. The wormhole closed, sparkling.

  The wreck - dark, almost bereft of energy - turned slowly in the stillness. It was empty of life.

  Almost.

  I’m still not sure how I survived. But I remember - I remember how the quantum functions came flooding over me. They were like rain-drops; it was as if I could see them, Spinner-of-Rope. It was painful. But it was like being born again. I was restored to time.

  It hadn’t taken Poole long to check out the status of the derelict his craft had become. There had been power in the lifedome’s internal cells, sufficient for a few hours, perhaps. But he had no motive power - not even a functioning data link out of the lifedome to the rest of his ship.

  I remember how dead the Universe looked. I couldn’t understand how the stars had got so old, so quickly; I knew I couldn’t have fallen more than a few million years.

  But I knew I was alone. I could feel it.

  I made myself a meal. I drank a glass of clear water . . . His face, softly translucent, was thoughtful. Do you know, I can remember the taste of that water even now. I had a shower . . . I was thinking of reading a book.

  But the lights went out.

  I felt my way back to my couch. I lay there. It started getting colder. I wasn’t afraid of death, Spinner-of-Rope. Strangely, I felt renewed.

  ‘But you didn’t die,’ she said. ‘Did you, Michael?’

  No. No, I didn’t die, said Poole.

  And then, a ship had come.

  Poole, dying, had stared up in wonder.

  It was something like a sycamore seed wrought in jet-black. Night-dark wings that spanned hundreds of miles loomed over the wreck of Poole’s GUTship, softly rippling.

  ‘A nightfighter,’ Spinner breathed.

  Yes. I got colder. I couldn’t breathe. But now I didn’t want to die. I wanted to live just a little longer - to understand what this meant.

  And then—

  ‘Yes?’

  And then, something had plucked Poole from the wreck. It was as if a giant hand had cupped his consciousness, like taking a flame from a guttering candle.

  And then it spun me out . . .

  Poole had become discorporeal. He no longer even had a heartbeat.

  He felt as if he had been released from the cave of bone that had been his head.

  I believe I became a construct of quantum functions, he said. A tapestry of acausal and nonlocal effects . . . I don’t pretend to understand it. And my companion was still there. It was like a huge ceiling over me.

  ‘What was it?’

  Perhaps it was Xeelee. Or perhaps not. It seemed to be beyond even the Xeelee - a construct by them, perhaps, but not of them . . .

  Spinner-of-Rope, the Xeelee were - are - masters of space and time. I believe they have even travelled back through time - modified their own evolutionary history - to achieve their huge goals. I think my companion was something to do with that programme: an anti-Xeelee, perhaps, like an anti-particle, moving backwards in time.

  I sensed - amusement, Poole said slowly. It was amused by my fear, my wonder, my longing to survive. She heard the faded ghost of bitterness in his voice.

  After a time, it dissolved. I was left alone. And, Spinner, I found I could not die.

  At first, I was angry. I was in despair. He held up his glowing hand and inspected it thoughtfully, turning it round before his face. I couldn’t understand why this had been done to me - why I’d been preserved in this grotesque way.

  But - with time - that passed. And I had time: plenty of it . . .

  He fell silent, and she watched his face. It was blank, expressionless; she felt a prickle of fear, and wondered what experiences he had undergone, alone between the dying stars.

  ‘Michael,’ she said gently. ‘Why did you speak to me?’

  His bleak expression dissolved, and he smiled at her. I saw a human being, he said. A man, dressed in skins, frost-bitten, in a fragile little ship . . . He came plunging through a wormhole Interface, uncontrolled, into this hostile future.

  It was an extraordinary event . . . So I - returned. I was curious. I probed at the wormhole links - and found you, Spinner-of-Rope.

  Spinner nodded. ‘He was Arrow Maker. He was my father,’ she said.

  Michael Poole closed his eyes.

  ‘ . . . Spinner-of-Rope,’ Louise Armonk said. She sounded urgent, concerned.

  ‘Yes, Louise.’

  ‘I don’t know what in Lethe is happening in that head of yours, but you’d better get it clear fast.’ Spinner heard Louise issue commands over her shoulder. ‘ . . . We’ve got a problem.’

  ‘What kind of probl
em?’

  ‘Listen to me, Spinner. Here’s what you must—’

  Louise’s voice died, abruptly.

  ‘Louise? Louise?’

  There was only silence.

  Spinner twisted in her couch. Behind her, the bulk of the lifedome loomed over the clean lines of the nightfighter, a wall of glass and steady light.

  But now a soft webbing, a mesh of barely visible threads, lay over the upper levels of the lifedome.

  ‘Lethe,’ Spinner hissed. ‘That’s string.’

  For the first time in several years, the Decks were filled with the wail of the klaxon.

  Morrow, hovering in the green-tinged air close to Deck Two, straightened from his work. His back ached pleasurably, and there was warm dirt and water on his hands; he felt a fine slick of sweat on his forehead.

  He looked around vaguely, seeking the source of the alarm.

  Milpitas, his sleeves rolled up and the deep scars of his face running with sweat, studied him. The Planner fingered a handful of reeds which protruded from the spherical pond. ‘Morrow? Is something wrong? Why the klaxon?’

  ‘I don’t know, Planner.’

  The sound of the klaxon was deafening - at once familiar and jarring, making it hard to think. Morrow looked around the Decks, at the tranquil, three-dimensional motion of people and ‘bots as they went about their business; in the distance the shoulders of the Temples loomed over the grass-covered surfaces. It all looked normal, placid; he felt relaxed and safe.

  Morrow was working with Milpitas within what had once been Poole Park. They were still trying to establish their zero-gee water feature. Milpitas and Morrow had set a ball of earth on a fine pole, attached it to the Deck surface, and surrounded it with a globe of water five feet across, restrained by a fine skin of porous plastic. Reeds and lilies were planted in the ball of earth, and were already growing out of the water surface. Their vision was that the reeds and lilies - perhaps plaited in some way - together with the water’s natural surface tension would eventually suffice to hold the pond together, and they could abandon the plastic membrane.

  Then, at last, they could populate the pond, with fish and frogs.