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

by Stephen Baxter

  The torus as a whole reminded her, distantly, of Saturn’s rings; it was a circle which spanned the galaxy-walled cavity.

  At first she thought the component speckles were mere points of light: they were like stars, she thought, or diamonds scattered against the velvet backdrop of the faded galaxy light. But as she looked more closely she could see that some of the nearer objects were not simple points, but showed structure of some kind.

  So these weren’t stars, she thought, and nor was this some attenuated galaxy: there were only (she estimated quickly) a few thousand of the shining forms, as opposed to the billions of stars in a galaxy . . . And besides, this cavity-spanning torus was immense: she could see how the blood-dark corpses of galaxies sailed through its sparse structure.

  She knew that the Galaxy of humans had been a disc of stars a hundred thousand light-years in diameter. This torus must be at least a hundred times as broad - more than ten million light-years across.

  She turned to Mark; he studied her face, a certain kindness showing in his eyes now. ‘I know how you’re feeling. It’s magnificent, isn’t it?’

  ‘It can’t be the Ring,’ she said slowly. ‘Can it? As far as we know, Jim Bolder reported a solid object - a single, continuous artifact.’

  ‘Look more closely, Lieserl. Cheat a little; enhance your vision. What do you see?’

  She turned her head and issued brisk subvocals. A section of the torus exploded towards her; the fragments, rushing apart, gave her a brief, disorienting impression of sudden velocity.

  Her view steadied. Now, it was as if she was within the torus itself, and the sparkling component objects were all around her.

  The fragments weren’t simple discs - or ellipses, or any of the shapes into which a star or galaxy might be distorted by the presence of others. She could see darkness within the heart of these objects.

  The fragments were knots.

  ‘Mark—’

  ‘You’re looking at loops of cosmic string,’ he said calmly. ‘This immense torus is made up of string knots, Lieserl - ten thousand of them, each a thousand light-years across.’

  She was aware of her hand convulsing closed around his. ‘I don’t understand. This is - fantastic. But it isn’t the Ring Bolder described.’

  He looked distant, wistful. ‘But it must be. We know we’ve come to the right place, Lieserl. This is undoubtedly the site of the Great Attractor: the loops, together, have sufficient mass to cause the local streaming of galaxies.

  ‘And we know this assemblage must be artificial. Primeval string loops could have formed during the formation of the Universe, after the singularity. But there should have been no more than a million of them - in the entire Universe, Lieserl - spaced tens of millions of light-years apart. It simply isn’t possible for a collection of ten thousand of the damn things to have gathered spontaneously within a cavity a mere ten million light-years across . . .’

  ‘But,’ Lieserl said patiently, ‘but Bolder said the Ring was solid. If he was right—’

  ‘If he was right then the Ring has been destroyed, Lieserl. These loops are - rubble. We’re looking at the wreckage of the Ring. The photino birds have won.’ He turned to her, his face a sculpture, expressionless, obviously artificial. ‘We’re too late, Lieserl.’

  She felt bewildered. ‘But if that’s true - where are we to go?’

  Mark had no answer.

  Louise said, ‘What are you talking about, Spinner?’

  ‘Can’t you see it?’ She closed her eyes and watched, once again, as the string loop punched through the fragile superstructure of the galaxy. ‘Mark - Louise - this string loop was aimed, quite precisely. It’s a weapon. It is blasting through this galaxy with its gravitational rockets, destroying all in its path with focused beams of electromagnetic and gravitational energy . . .’

  Louise snapped, ‘Mark?’

  Mark hesitated. ‘We can’t prove she’s right, Louise. But the chances of the loop hitting such a precise trajectory at random are tiny . . .’

  ‘It seems crazy,’ Morrow said. ‘Who would dare use a thousand-light-year loop of cosmic string as a weapon of war?’

  Uvarov grunted. ‘Isn’t that obvious? The very entities we have come all this way to seek, from whom we hope to obtain shelter - the Xeelee, Morrow; the baryonic lords.’

  ‘But why?’ Mark asked. ‘Why destroy a galaxy like this?’

  ‘In defence,’ Uvarov snapped.

  ‘What?’

  ‘Isn’t that clear too? The Xeelee were masters of the manipulation of spacetime. Their weaponry consisted of these immense structures of spacetime flaws. And the flaws have been used against the weapons of their enemies - like this galaxy .’

  There was silence for a moment. Then Morrow said, ‘Are you insane, Uvarov? You’re saying that this galaxy has been hurled like some rock - deliberately?’

  ‘Why not?’ Uvarov replied calmly. ‘The photino birds are creatures of dark matter - which attracts baryonic matter gravitationally. We can easily imagine some immense dark chariot hauling at this fragile galaxy, hurling it hard through space . . .

  ‘Think of it. The photino birds must have begun to engineer the deflection of this galaxy’s path many millions of years ago - perhaps they were intent on launching this huge missile at the Ring long before men walked on the Earth. And the Xeelee must have been preparing their counter, this loop of string, over almost as great a timescale.’

  Now Spinner-of-Rope felt a bubble of laughter, wild, rise in her own throat. She had an absurd image of two giants, bestriding the curving Universe, hurling galaxies and string loops at each other like lumps of mud.

  ‘We are truly in the middle of a war zone,’ Uvarov said coldly. ‘This galaxy, with the bullet of cosmic string aimed so accurately at its heart, is merely one incident among ten million in a huge battlefield. To our fleeting perceptions the field is frozen in time - we buzz like flies around the bullet as it hurtles into the chest of its target - and yet the battle rages all around us.’

  Don’t be afraid.

  Spinner closed her eyes and thought of the forest dream man, smiling at her from his tree and eating his fruit . . .

  I know who this is, she realized suddenly. I’ve seen his face, in Louise’s old Virtuals . . .

  ‘I know you,’ she told him.

  Yes. Don’t be afraid, said Michael Poole.

  28

  Louise Armonk asked Spinner to take the nightfighter to the source of Mark’s anomalous hydrogen-band signal.

  She showed Spinner some data on the signal. ‘Here’s a graphic of the main sequence, Spinner-of-Rope.’ A barchart, in gaudy yellow and blue, marched across Spinner’s faceplate. ‘We’re getting pretty excited about this. For one thing it’s periodic - the same pattern recurs every two hours or so. So we’re pretty sure it has to be artificial. And look at this,’ Louise said. A sequence of thirty bars, buried among the rest, was now highlighted with electric blue. ‘Can you see that?’

  Spinner looked at the ascending sequence of bars, trying hard to share Louise’s excitement. ‘What am I looking for, Louise?’

  She heard Louise growl with impatience. ‘Spinner, the amplitude of these pulses is increasing, in proportion with the first thirty prime numbers.’

  The electric-blue bars were split into discrete blocks, now, to help Spinner see the pattern. She counted the blocks: one, two, three, five, seven . . .

  She sensed an invisible smile. Just like a child’s puzzle, isn’t it?

  ‘Oh, shut up,’ she said easily.

  ‘What was that?’

  ‘Nothing . . . I’m sorry, Louise. Yes, I see it now.’

  ‘Look - what’s exciting about finding this sequence of primes is that it means the signal is almost certainly human.’

  ‘How do you know that, just from this pattern?’

  ‘We don’t know for sure, of course,’ Louise said impatiently. ‘But it’s a damn good clue, Spinner-of-Rope. We’ve reason to believe the prime numbers are
of unique significance to humans.

  ‘The primes are fundamental structures of arithmetic - at least, of the discrete arithmetic which seems to come naturally to humans. We are compact, discrete creatures: I’m here, you are out there somewhere. One, two. Counting like this seems to be natural to us, and so we tend to think it’s a fundamental facet of the Universe. But it’s possible to imagine other types of mathematics.

  ‘What of creatures like the Qax, who were diffuse creatures, with no precise boundaries between individuals? What of the Squeem, with their group minds? Why should simple counting be natural to them? Perhaps their earliest forms of mathematics were continuous - or perhaps the study of infinities came naturally to them, as naturally as arithmetic to humans. With us, Cantor’s hierarchy of infinities was quite a late development. And—’

  Spinner barely listened. Humans? Here, at the edge of time and space? ‘Louise, have you decoded any of the rest of it?’

  ‘Well, we can figure some of it out,’ Louise said defensively. ‘We think, anyway. But remember, Spinner, we may be dealing with humans from a culture far removed in time from our own - by millions of years, perhaps. The people of such a distant future could be almost as remote from us as an alien species. Not even Lieserl has been able to help us work this out . . .’

  ‘But you’ve made some progress. Right?’

  Louise hesitated. ‘Yes. We think it’s a distress call.’

  ‘Oh, great. Well, we’re certainly in a position to help out god-humans from five million years after our birth.’

  ‘Who knows?’ Louise said dryly. ‘Maybe we are. Anyway, that’s what we’re going to find out.’

  . . . There was motion at Spinner’s left. She turned.

  Suddenly, the forest-dream man was visible. He was sitting there, quite casually - outside the cage - on the construction-material shoulder of the nightfighter. He wore no environment suit, nothing but a plain grey coverall. His hands were folded in his lap. Light - from some unseen source - caught the lines around his mouth, the marks of tiredness in his eyes.

  At last he had emerged. Gently, he nodded to her.

  She smiled.

  ‘ . . . Spinner?’

  ‘I’m here, Louise.’ She tried to focus her attention on her tasks; she reached for the hyperdrive waldo. ‘Are you ready?’

  ‘Yes.’

  The nightfighter flickered through hyperspace. Travelling at more than a hundred thousand light-years per hour, the Northern edged around the torus of fragmented string loops, like a fly around the rim of a desert.

  The journey took ten hours. As it neared its end Spinner-of-Rope took a brief nap; when she woke, she had her suit’s systems freshen her skin, and she emptied her bladder.

  She checked a display on her faceplate. Twenty jumps to go. Twenty more seconds, and—

  Something vibrant-blue exploded out of space at her, ballooning into her face.

  She cried out and buried her faceplate in her arms.

  It’s all right, Poole said softly.

  ‘I’m sorry, Spinner-of-Rope,’ Louise Armonk said. ‘I should have warned you . . .’

  Spinner lowered her arms, cautiously.

  There was string, everywhere.

  A tangle of cosmic string, rendered electric blue by the faceplate’s false colouring, lay directly ahead of the ship. Cusps, moving at lightspeed, glittered along the twisted lengths. She leaned forward and looked up and down, to left and right; the threads of string criss-crossed the sky as far as she could see, a textured wall across space. Looking deeper into the immense structure, Spinner saw how the individual threads blurred together, merging into a soft mist at infinity.

  The string loop was a barrier across the sky, dividing the Universe in two. It was quite beautiful, she thought - but deadly. It was a cosmic web, with threads long enough to span the distances between stars: a web, ready to trap her and her ship.

  And, she knew, this was just one thousand-light-year fragment, among thousands in the torus . . .

  ‘Lethe,’ she said. ‘We’re almost inside this damn thing.’

  ‘Not quite,’ Louise said. Her voice, nevertheless, was tight, betraying her own nervousness. ‘Remember your distance scales, Spinner. The string loops in this toroidal system are around a thousand light-years across. We’re as far from the edge of that loop as the Sun was from the nearest star.’

  ‘Except,’ Mark Wu cut in, ‘that the loop has no easily definable edge. It’s a tangle. Cosmic string is damn hard to detect; the display you’re looking at, Spinner, is all Virtual reconstruction; it’s just our best guess at what lies out there.’

  ‘Then are we at risk by being here?’ Spinner asked.

  Of course, Michael Poole said.

  ‘No,’ Louise said.

  ‘Yes,’ Mark said. ‘Come on, Louise. Spinner, we’re working to minimize the risks. But the danger is there. Spinner, you need to be ready to react - to get us out of here, quickly. We have escape routines laid into the waldoes, for both hyperdrive and discontinuity drive.’

  ‘I’ll be ready,’ she said calmly. ‘But why are we here? Is the human signal coming from somewhere in there - inside the string?’

  ‘No,’ Louise said. ‘Thankfully. Spinner, the signal is coming from the system of a neutron star - just a few light-hours away from here. We’ve laid in—’

  ‘—a discontinuity-drive sequence into the waldoes,’ Spinner said dryly. ‘I know.’ She reached for her controls. ‘Tell me when you’re ready, Louise.’

  Poole looked tired, his brown eyes deep in a mesh of wrinkles. You know, I worked with Louise Armonk, he said. He smiled. And here we are, together again. Small world, isn’t it? She was a good engineer. I guess she still is.

  ‘I know you decided to close your wormhole time bridge,’ Spinner said. ‘Tell me what happened to you.’

  Poole sat, apparently relaxed, on the ‘fighter shoulder; his eyes were closed, his head bent forward. I remember the lifedome of my GUTship entering the Interface, he said slowly. There was light - like fire, blue-violet - from all around the lip of the dome. I knew that was the flesh of the Spline, burning up against the Interface’s exotic-matter framework. I remember - a sense of loss, of alienation.

  ‘Loss?’

  I was passing out of my time frame. Spinner-of-Rope, each of us - (he raised translucent hands) - even I - is bound into the world by quantum functions. I was linked non-locally to everything I had touched, seen, tasted . . . Now, all those quantum bonds were broken. I was as alone as any human had ever been.

  I engaged the hyperdrive.

  Bits of the wormhole seemed to fall away. I remember streams of blue-white light . . . I almost believed I could feel those hard photons, sleeting through the lifedome.

  Spacetime is riddled with wormholes: it is like a sheet of flawed glass, crazed by cracks. When Poole set off his hyperdrive inside the wormhole, it was as if someone had smashed at that flawed glass with a hammer. Cracks exploded out from the point of impact and widened; they joined up in a complex, spreading network of cracks, a tributary pattern that continually formed and reformed as spacetime healed and shattered anew.

  The spacetime cracks opened up like branching tunnels, leading off to infinity . . . Poole smiled, self-deprecating. I started to wonder if this had been a good plan, after all.

  The pod sailed down from the Northern’s lifedome.

  Lieserl sat in a Virtual projection of a pod couch beside Mark Wu; ahead of them blind Uvarov was swathed in his blankets, his cavern of a mouth gaping, his breath a rattle. The huge discontinuity-drive wings of the nightfighter spread over the pod like the vaulted roof of some immense church.

  Far below the pod revolved the bleak, airless planet to which they were descending. Staring down as the small island of solidity loomed out of the glowing fog, Lieserl had a sudden - and quite absurd - feeling of vertigo. She felt as if she were suspended, in this couch, without protection far above the planet’s surface; she had an impulse, which she suppres
sed with determination, to grip the sides of her couch.

  Vertigo . . . After all her experiences inside the Sun, and despite her perfect knowledge that she couldn’t be harmed even if the pod exploded here and now - since she was little more than a Virtual projection from the Northern’s main processors, with augmentation from the pod’s processor banks - after all that, she had vertigo.

  Still, she thought, it was comforting to know that she’d retained enough humanity to be just a little scared. Maybe she should tell Mark; it might make him think a little better of her.

  Beyond the pod’s clear hull, the neutron star system was a huge tableau all around them.

  The neutron star itself was a tiny, fierce yellow-red ball. It had a companion - a normal star - and it was surrounded by a ring of gas, which glowed softly. And there were several planets, orbiting the neutron star, inside the smoke ring.

  In fact, the anomalous signal was coming from one of the planets, the little world towards which Lieserl was now descending.

  The nightfighter had dropped them into the ring of smoke which orbited the star. It was like descending into fog. Close to the pod Lieserl could see dense swirls of the ring gas - clumps and eddies of turbulent stuff - and, beyond that, the rest of the ring was a band of pale light bisecting the Universe. She could see the neutron star itself, a small, hard coal glowing yellow-red at the heart of this ring of smoke. Beside it hung its companion star - huge, pale, distorted into a squat egg-shape by the neutron star’s fierce gravitational field. Tendrils of gas led from the carcass of the companion and reached blindly towards the neutron star.

  And beyond that, tilted crazily compared to the gas torus, was a starbow.

  This neutron star was moving with extraordinary speed: it plummeted across space at close to the speed of light. As a result of this high velocity, the neutron star and its system were the only visible objects in Lieserl’s Universe. All of the rest - the blue-shifted galaxies, the nearby wall of cosmic string - was compressed into that pale starbow, a band of light around the equator of the star’s motion. And away from the starbow, there was only darkness.