Ring xs-4

by Stephen Baxter

  “These are what we call Population III stars, Spinner. Or VMOs — ‘Very Massive Objects’.”

  “If they are so massive,” Spinner said slowly, “then I guess they won’t last so long as stars like Sol.”

  Louise looked at her appreciatively. “That’s perceptive, Spinner. You’re right. The VMOs burn their hydrogen fuel quickly. Each of these is going to stay on its Main Sequence for no more than a few million years — two or three, at best. The Sun, on the other hand, should have survived for tens of billions of years, without the interference of the photino birds.”

  “What then?” Spinner asked. “What do we do when New Sol goes out?”

  Morrow smiled. “Then, I guess, we move on: to another star, and another, and another… We have time here to work that out, I think, Spinner-of-Rope.”

  Now New Sol was rising again, over the lip of the pod. The four of them turned instinctively to the light, its flat whiteness smoothing the lines of age and fatigue in their faces.

  “In fact,” Mark said, “the star we’ve chosen — New Sol — is already well past its middle age. It’s probably got no more than three-quarters of a million years of its life left.”

  Spinner frowned. “That seems stupid. Why not choose a young star, and move there while we can? It may be that when New Sol dies we won’t be able to move away.”

  “No,” Mark said patiently. “Spinner, we need an older star.”

  The star called New Sol was nearing the end of the second phase of its existence. In the first, it had burned hydrogen into helium. Now, helium was fusing in turn, and a rain of more complex elements had formed a new, inner core: principally oxygen, but also neon, silicon, carbon, magnesium and others.

  And later, in the third phase of its life, when the oxygen started to burn, the star would die… although how was far from certain.

  “Terrific,” Spinner said. “And we die with it.”

  “No,” Mark said seriously. “Spinner-of-Rope, we die without it. Don’t you get it? New Sol is full of oxygen…”

  Morrow was pointing, excitedly. “Look. Look. There’s the wormhole… I think it’s almost time.”

  Louise turned in her seat.

  Now a new form emerged over the rotating pod’s horizon: the familiar shape of a wormhole Interface. This Interface was only a hundred yards across — far smaller than the mile-wide monster the Northern had hauled across a different spacetime — but, like its grander cousins of the past, it shared the classic tetrahedral frame, the shining electric blue color of its exotic matter struts, and the autumn-gold glimmering of its faces. A dozen drone scoop-ships prowled around the Interface, patient, waiting.

  Louise felt a prickle of tears in her eyes; she brushed them away impatiently. Already, she thought, we are building things here. Already, we are engineering this universe.

  Mark said to Spinner, “If there were planets here we could land and try to terraform one. But there are no planets for us to land on. Anywhere. This is a very young universe. There are no more than traces of heavy elements here, anywhere, outside the interior of the protostars. There are no moons, no comets, no asteroids… We have no raw materials to build with, save the hulk of the Northern — save what we brought here ourselves. We can’t even renew our atmosphere.”

  Morrow nodded. “So,” he said, “we’re mining the star.”

  The second terminus of this wormhole had been dropped into the carcass of New Sol. Lieserl had accompanied the Interface — just as once she had traveled into the heart of Sol itself. Soon, enriched gases from the heart of the new star would pour into space — here, far from the heat of New Sol, accessible.

  The scoop-ships had mouths constructed of electromagnetic fields which could gather in the star-dust across volumes of millions of cubic miles. When the wormhole started to operate, the scoops would sift out the few grains of precious heavy elements.

  “The first priority is atmospheric gases,” Mark said. “We lost a lot of our recyclable reserve during the string impact. Another blow-out like that and we’d be finished.”

  “Are all the gases we need there, inside the star?”

  “Well, there’s plenty of oxygen, Spinner,” Louise said. “But that’s not enough. An all-oxygen atmosphere isn’t particularly stable — it’s too inflammable. We need a neutral buffer gas, to contribute to the hundreds of millibars of pressure we need to stay alive.”

  “Like nitrogen,” Spinner said.

  “Yes. But there isn’t much nitrogen in New Sol. We should be able to use neon, though…”

  “We can replace our other stores. Use the oxygen to make water and food.”

  “We can do more than that, Spinner-of-Rope,” Mark said. “In the longer term we can extract heavier elements: magnesium, silicon, carbon — maybe even iron. They are only present in traces in New Sol, but they’re there. We can build a fleet of Northerns, if we’re patient enough. Why, we can even make rocks.”

  Spinner looked out at New Sol, and the point light glittered in her eyes, making her look very young, Louise thought. Spinner said, “It’s chilling to think that — except maybe for the Xeelee — we’re alone here, in this universe. Stars like this once burned in our Universe — but they were all extinguished, destroyed, long before humans became conscious.

  “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 p
ossible. 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 vigor, 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 super giant, 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 toward 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 percent 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 formed 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 fueled 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.