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

by Stephen Baxter

  ‘We may survive for millions of years here. But, finally, we’ll be gone. New Sol, and all these other stars, will destroy themselves. Eventually, a new generation of stars will form in the enriched galaxies - stars like Sol. And, I guess, intelligence will arise here . . .

  ‘But not for billions of years after we’re gone.’

  Spinner turned to Louise, her eyes large, her expression fragile, troubled. Her hands tugged at each other’s fingers, and played with the arrow-head pendant at her chest. ‘Louise, nothing we build could survive such a length of time. No conceivable monument, or record, could persist. We’ll be forgotten. No one will ever know we were here.’

  Louise reached over the back of her chair and took Spinner’s hands in hers, stilling their nervous motions. Again she felt a surge of responsibility for Spinner’s fragile state. ‘That’s not true, Spinner,’ she said gently. ‘We’ll still be there. These VMOs will leave traces in the microwave background - peaks of energy against the smooth radiation curves. There were traces like that in the microwave spectrum of our own Universe - that’s how we know of our own primordial VMOs. And there will be other traces, relics of this time. These giant proto-stars will enrich the substance of the young galaxies here, with heavy elements. Without the heavy elements stars like old Sol could never form . . . and we’ll be part of that enrichment, Spinner-of-Rope, tiny traces, atoms which formed in a different universe.’

  Spinner-of-Rope frowned. ‘A blip in the microwave background? Is that to be our final monument?’

  ‘It might be sufficient to let the people of the future work out that we were here, perhaps. And besides, we might have a billion years ahead of us, Spinner. Time enough to think of something.’ She stroked Spinner’s hands. ‘It would take a long time, but we could build a planet for ourselves, out here on the lip of New Sol’s gravity well.’ She smiled. Maybe they could construct an ocean, wide enough for the Great Britain to sail again. What would old Isambard have made of that? And—

  ‘No,’ Morrow said mildly.

  Louise turned to him, surprised. His face, gaunt, shaven of hair, was smooth and confident-looking in the light of New Sol.

  ‘What did you say?’ Louise asked.

  He turned to her. ‘Planets are inefficient, Louise. Oh, they’re convenient platforms if they exist already. But - to build a planet? Why bury all that painfully extracted matter inside your habitable surface?’

  Louise found herself frowning; she was aware of Mark grinning at her, irritatingly. ‘But what’s the alternative?’

  Morrow said, ‘We can build structures in space: rings, hollow spheres - the point is to maximize the habitable surface available for a given mass - to spread it out as much as possible. Louise, a spherical planet gives you a minimum surface for a given mass.’

  Louise studied Morrow curiously. His motion sickness was still evident in the pallor of his thin face, but he spoke with a vigour, a clarity she wouldn’t have believed possible when she’d first met him, soon after his emergence from the Decks. Was it possible that the centuries of oppression, of body and soul, which he had endured in there, were at last beginning to lift?

  Mark smiled at her. ‘You’d better face it, Louise. You and I grew up on worlds, and so we think in terms of rebuilding what we’ve lost. We’d better move aside, and leave the future to these bright young kids.’

  She found herself grinning back. She whispered, ‘Okay, I take your point. But - Morrow, as a bright young kid?’

  ‘Maybe we’ll just build ships,’ Spinner said intently. ‘Whole armadas of them. We can simply fly; who needs to land, anyway? We could spread out, here. Maybe the Xeelee are here already - we came through their gateway, after all. We could see if we can find them . . .’

  Mark scratched his chin. ‘That’s a good agenda, Spinner-of-Rope. You know, I think Garry Uvarov would be proud of you.’

  She glared at him. She pulled her hands away from Louise, and for a moment - with her streak of scarlet face paint, and spectacles glinting with New Sol light - Spinner reminded Louise of the savage little girl she’d once been.

  ‘Maybe he would,’ Spinner snapped. ‘But so what? I’m not a creation of Garry Uvarov. Uvarov was an oppressor, insane.’

  Louise shrugged. ‘Perhaps he was, in the end - and capricious. But he was also insightful, iconoclastic. He never let us turn away from the truth, in any situation, no matter how uncomfortable that was . . .’

  Uvarov hadn’t deserved to die, blind and alone, in a remote, deserted future. Maybe Uvarov had been right, too, in the motives behind his great eugenics experiment. Not in his methods, of course . . . But perhaps a natural, technology-independent immortality was a valid goal for the species.

  Louise was aware that she and her crew had gone to a great deal of trouble to preserve the essence of humanity, through the collapse of the baryonic Universe. They hadn’t sent mere records of humankind through the Ring, or Virtual representations of what man had been: they’d brought people, with all their faults and ambiguities and weaknesses, and plumbing. And now that they’d succeeded, perhaps it was time for human stock to begin to develop: to face up to and exceed the limitations, of body and spirit, which had, at last, caused the extinction of humanity in the old, abandoned Universe.

  She wondered if, in several generations’ time, the descendants of Spinner-of-Rope would indeed sail through this new universe in their sparkling ships. Perhaps when they finally met the Xeelee, it would be on equal terms; perhaps the new humans would be strong, immortal - and sane.

  ‘ . . . It’s starting!’ Morrow said, his voice high and tense. He pointed, his sleeve riding up his arm. ‘Look at that.’

  In a sudden eruption of light, gas blossomed from the four faces of the Interface. Still fusion-burning as it emerged, the gas rapidly expanded into a growing, cooling cloud. Louise could see the tetrahedral form of the Interface itself at the blazing heart of this animated sculpture of gas.

  Diffuse light flooded the pod. It was as if a new, tiny star had ignited, here on the fringe of New Sol’s gravity well. The drones flickered open their electromagnetic scoops and moved into the glowing, dispersing clouds, browsing patiently.

  ‘Lethe’s waters,’ Morrow breathed. ‘It’s beautiful. It’s like a flower.’

  ‘More than that, Mark said with a grin. ‘It’s beautiful because it’s bloody worked.’ He turned to Louise, his blue eyes brilliant, and his face looked youthful and alive.

  ‘Louise,’ he said, ‘I think we might live through this after all.’

  Louise reached for the pod’s controls. The first loads of atmospheric gases would be arriving soon. And there were homes to be built. It was time to return to the Northern and get back to work.

  Life would go on, she thought: as complicated, and messy, and precious, as ever.

  Once again Lieserl spread her arms and soared through the interior of a star. But now her playground was no mere G-type yellow dwarf like the Sun: this was New Sol - a supergiant, salvaged for her from the dawn of time, fully ten million miles across.

  Lethe’s waters. I’d forgotten how wonderful this feels - how restrictive a human body could be . . .

  I was born for this, she thought.

  She arced upwards towards the photosphere - the star’s surface was a wall of gas which seared space at a temperature of a hundred thousand degrees - and then she dived, yelling, down into the core. In Sol, the fusing core had been confined to the innermost few per cent of the diameter. Here, the core was the star, extending out almost to the photosphere itself. There was fusion burning everywhere. All around her helium burned into oxygen, dumping prodigious quantities of heat energy into the star’s opaque flesh. In response, immense convective cells - some of them large enough to have swallowed Sol itself - surged through the interior.

  This star was no more than a couple of million years old. But already - to her intense regret - she’d missed one of the most interesting phases of its existence.

  The star had for
med as a ball of fusing hydrogen, two thousand times more massive than the Sun. There had been convection cells then, too, which had driven instabilities in the giant star; it had breathed, swelling and contracting through fully a tenth of its diameter in a day. The instabilities had grown, exponentially, resulting at last in the casting off of huge shells of material from the surface of the star, like a series of repeated nova explosions; the Northern had sailed in through those ancient shells, on its way to its orbit around the new sun.

  Meanwhile, the helium core had grown, and steadily contracted, and heated up.

  At last, the core reached half the mass of the original VMO - about a thousand Solar masses. And a shell of hydrogen around the core ignited.

  The mass of three Suns was flashed to energy within mere hours - expending energy that could have fuelled Sol for ten billion years of steady burning. The wind from the explosion stripped off the still-fusing envelope, creating another expanding shell around a remnant helium star.

  Now, as Lieserl flew through the star, the helium was in turn burning to oxygen, which was being deposited in the star’s core. Eventually, the oxygen would ignite. And then—

  And then, the outcome wasn’t certain. Her processors were still working on predictions: gathering data, developing scenarios. It all depended on critical values of the star’s mass. If the mass was low enough the star could survive, for many millions of years, its diameter oscillating slowly . . . and rather dully, Lieserl thought. But a little larger and the star could destroy itself in a supernova explosion - or, if massive enough, collapse into a black hole.

  Lieserl studied the data streams trickling into her awareness. She would know soon. She felt a shiver of excitement. If the star was unstable, the end would come well within a million years. And then—

  . . . Lieserl?

  The voice of Louise Ye Armonk broke into her thoughts. Damn. Lieserl lifted her arms over her head and plunged into a huge convection fountain; the fusing star-stuff played over her Virtual body, warming her to the core.

  But she couldn’t escape Louise’s voice, any more than she’d been able to outrun Kevan Scholes.

  Come on, Lieserl. I know you can hear me. I’m monitoring your data feeds, remember—

  Lieserl sighed. ‘All right, Louise. Yes, I can hear you.’

  Lieserl - Louise hesitated, uncharacteristically.

  ‘I think I know what you’re going to say, Louise.’

  Yes. I bet you do, Louise growled. Lieserl, we’re grateful to you for going into New Sol with the wormhole Interface. And you’re sending us a lot of great data. But . . .

  ‘Yes, Louise?’

  Lieserl, you didn’t leave a back-up.

  ‘Ah.’ Lieserl smiled and closed her eyes. The neutrino flux from the heart of New Sol brushed against her face, as delicate as a butterfly’s wing. ‘I wondered how long it would take you to notice that.’

  Damn it, Lieserl, that’s the only copy of you in there!

  ‘I know. Isn’t it wonderful?’

  You don’t understand. What if something happened to you? Louise went on heavily, Lieserl, we’ve never dropped a wormhole into a VMO before. We’re not sure what will happen.

  ‘No. Well, before my day no one had ever dropped a wormhole into Sol. Nothing much changes, does it?’

  Damn it, Lieserl. I’m trying to tell you that you could die.

  ‘Don’t you think I know that? Don’t you see - that’s the whole point?’

  Louise didn’t reply.

  ‘Louise, I’m very old. I’ve watched my birth star grow old and die. I’m grateful to you for retrieving me from Sol: I wouldn’t have missed that ride through the Ring for . . . for half my memory store. But, Louise, I don’t think I can be a human any more - not even a Virtual copy of one. And I don’t want to build worlds . . . that is for Spinner-of-Rope, and Trapper, and Painter-of-Faces, and the other children from the forest and the Decks. Not for me.’

  Lieserl, do you want to die?

  ‘Oh, Louise. I’ve already died once - or so we think, on the neutron star planet with poor Uvarov - and I never even felt it. I don’t want to go through that again.

  ‘This is where I want to be, Louise. Here, inside this new star.’ She smiled.

  ‘It’s what I was designed for, remember.’

  Louise was silent for a while. Then: Come home, Lieserl.

  ‘Louise - dear Louise - I am home.’

  Lieserl—

  Wistfully, she shut off the voice link to the Northern. She’d open it later, she told herself: when Louise had grown accustomed to the idea that Lieserl was here - here and nowhere else - and here she was going to stay.

  And in the meantime, she realized with growing excitement, the processors lodged in the refrigerating wormhole had come to a conclusion about the destiny of her star, New Sol.

  She called up a Virtual image of the star; it rotated before her, a crude onion shell.

  Already, she knew, oxygen was burning in pockets throughout the star, depositing the more complex elements - carbon, silicon, neon, magnesium - for which the wormhole was designed to trawl. With time, the helium-burning core of the star would contract, leaving a mantle of cooling helium and ash around a centre growing ever hotter.

  At length - perhaps in half a million years, the processors concurred - oxygen burning would start in earnest in the core . . .

  With growing excitement Lieserl watched the Virtual diorama, ready to learn how she would die.

  When oxygen burning started in the core, the star would become immediately unstable.

  The mantle would explode. The rotating star would start to collapse, asymmetrically.

  Then the core would implode, precipitously.

  The giant star’s gravitational binding energy would be converted into a flood of neutrinos, billowing through the collapsing core. Some of the neutrinos would be trapped by the implosion of the core. Others, in the last few milliseconds before the VMO’s final collapse into a black hole, would escape as an immense neutrino pulse . . .

  She remembered the first seconds of her life: her mother’s hands beneath her back, a dazzling light in her eyes. The Sun, Lieserl. The Sun!

  In the last moments of her long life, a neutrino fireball would play across the bones of her face.

  Lieserl smiled. It would be glorious.

  35

  Time passed. After a certain point, even the measurement of time became meaningless. For Michael Poole this moment arrived when there was no nuclear fuel left to burn anywhere, and the last star flickered and died.

  Already the Universe was a hundred thousand times its age when the Xeelee left.

  Sombrely Poole watched the stars evaporate, through collisions, from the subsiding husks of galaxies, or slide into the huge black holes forming at the galactic centres. Then, as the long night of the cosmos deepened, even protons collapsed, and the remaining star-corpses began to crumble.

  Poole wearied of puzzling over the huge, slow projects of the photino birds.

  He sought out what had once been a neutron star. The carbon-coated sphere, drifting in orbit around a gigantic black hole, was being warmed - at least, kept to a few degrees above absolute zero - by proton decay within its bulk. Poole, as if seeking comfort, clustered his attention foci close to this shadow of baryonic glory.

  Maybe there were other baryonic sentients left in the Universe. Maybe there were even other humans, or human derivatives. Poole did not seek them out. With the closure of the Ring, the baryonic story was done.

  Michael Poole, alone, huddled close to the chill surface of the neutron star. His awareness sparkled and subsided.

  The river of time flowed, unmarked, towards the endless seas of timelike infinity.

  TIMELINE

  This outline timescale provides the context for the novels in this collection, as well as those of the ‘Destiny’s Children’ series (Coalescent, 2003, Exultant, 2004, Transcendent, 2005). For a full timeline of the ‘Xeelee Sequence’ of novels and
stories, please see www.stephen-baxter.com.