Ring xs-4

by Stephen Baxter

  The photino birds clustered around the Sun’s shrinking heart, sipping relentlessly at its energy store. She was outside the bulk of the flock now although some outriders still swept past her, on their way into the flock from the Universe outside. With a new feeling of detachment, she started to experience a deepening sense of disquiet at the activities of the birds. From this perspective, the birds seemed like carrion, she thought, or tiny, malevolent parasites.

  Restless, disturbed, Lieserl moved through the huge envelope. There was structure here, even in this immense volume, she saw. The photosphere of the new red giant — its huge, glowing surface — had actually become less opaque to radiation; its temperature had fallen so far that electrons had recombined with nuclei, increasing the transparency of the surface layers. So — even though its surface temperature had dropped — the Sun was actually radiating more energy, overall, than it had done before its swelling.

  To fuel this increased luminosity, immense convection cycles had started — cells which spanned millions of miles, and which would persist for hundreds of days. The convection cycles dug deep into the mantle to haul energy out of the core regions to be pumped out to space — and along with the energy dredging, Lieserl saw, the convection was changing the composition of the Sun, polluting the outer regions with nucleosynthesis products like nitrogen-14, dug out of the core regions.

  Coherent maser radiation flashed along the flanks of the convection cells, startling her with its intensity.

  As she traveled through the thin gas she felt a faint buffeting, a rocking of the exotic-matter framework of her Interface.

  There was turbulence here. The convection process wasn’t perfectly efficient, and energy, struggling to escape from the inner regions, was forced to dissipate itself in a complex, space-filling array of turbulent cells. The Sun’s magnetic field was affected by this turbulence. She saw how the flux was pushed out of the interior of the cells, to form fine sheets across the cells’ surfaces — but the sheets were unstable, and they burst like sheets of soap film, leaving ropes of flux at the intersections of the turbulence cells. Lieserl swam through a million-mile mesh of the magnetic flux ropes.

  It was bizarre to think that — if she wished — she could travel out as far as the old orbital radius of Earth, without ever leaving the substance of the Sun.

  Lieserl knew — with remote, abstract sadness — that the inner planets, out as far as Earth, must have been consumed in the Sun’s cooling, red-tinged mantle. She remembered her brief, golden childhood: the sparkling beaches of the Aegean, the sharp, enticing scent of the sea, the feel of sand between her babyish toes. Perhaps humans, somewhere, were still enjoying such experiences.

  But Earth, the only world she had known, was gone forever.

  13

  “Arrow Maker, tell me what you see. Can you see the stars?”

  Arrow Maker looked down, through the pod hull. “I don’t understand.”

  Uvarov’s voice, disembodied, became ragged; Arrow Maker imagined the old man thrashing feebly beneath his blanket. “Can you see Sol? You should be able to, by now. Arrow Maker — is Earth there? Is — ”

  “No.”

  “Maker — ”

  “No.”

  Arrow Maker shouted the last word, and Uvarov subsided.

  The illuminated lip of the port had passed right over the pod now; it was visible to Maker as a frame of light above his head. The outer darkness had enclosed the pod… No, he was thinking about this in the wrong way. The darkness was the Universe; as if in some obscene, mechanical birth, the pod had been expelled from the lifedome into the dark.

  The base of the lifedome hung over him like a huge belly of glass and metal, receding slowly, its curvature becoming apparent. And through it — distorted, rendered misty by the base material — he made out the light-filled interior of the dome. He could see bits of detail: elevator shafts from the decks above, control consoles like the one at which he’d left Spinner, Morrow and Uvarov — why, if he had eyes sharp enough, he could probably look up now and see the soles of his daughter’s feet.

  Suddenly the reality of it hit him. He had traveled outside the lifedome. He was beyond its protective hull — perhaps the first human to have ventured outside in half a millennium — and now he was suspended in the emptiness which made up most of the forbidding, lifeless Universe.

  “Arrow Maker. Talk to us.”

  Arrow Maker laughed, his voice shrill in his own ears. “I’m suspended in a glass bubble, surrounded by emptiness. I can see the lifedome. It’s like — ”

  “Like what?” Morrow’s voice, sounding intrigued.

  “Like a box of light. Quite — beautiful. But very fragile-looking…”

  Uvarov cut in, “Oh, give me strength. What else, Arrow Maker?”

  Arrow Maker twisted his head, to left and right.

  To the right of the pod, an immense pillar of sculpted metal swept through space. It was huge, quite dwarfing the pod, like the trunk of some bizarre artificial tree. It merged seamlessly with the lifedome, and it was encrusted with cups, ribs and flowers of shaped metal.

  Maker described this.

  “The spine,” Uvarov said impatiently. “You’re traveling parallel to the spine of the GUTship. Yes, yes; just as I told you. Arrow Maker, can you see the Interface? The wormhole — ”

  Arrow Maker leaned forward and peered down, past the seats and stanchions, through the pod’s base. This spine descended for a great distance, its encrustation of parasitic forms dwindling with perspective, until the spine narrowed to a mere irregular line. The whole form was no less than three miles long, Uvarov had told him.

  Beyond the spine’s end was a sheet of light which hid half the sky. The light was eggshell-blue and softly textured; it was like a vast, inverted flower petal, ribbed with lines of stronger, paler hue. As Arrow Maker watched he could see a slow evolution in the patterns of light, with the paler lines waving softly, coalescing and splitting, like hair in a breeze. The light cast blue highlights, rich and varying, from the structures along the spine.

  He was looking at the GUTdrive: the light came from the primeval energies, Uvarov had told him, which had hurled the ship and all its cargo through space and time for a thousand years.

  Silhouetted against the sheet of creation light, just below the base of the spine, was a dark, irregular mass, too distant for Arrow Maker to resolve: that was the tethered ice asteroid, which still — after all these years — patiently gave up its flesh to serve as reaction mass for the great craft. And -

  “Uvarov. The Interface. I see it.”

  There, halfway down the spine’s gleaming length, was a tetrahedral structure: edged in glowing blue, tethered to the spine by what looked like hoops of gold.

  “Good.” He heard a tremulous relief in Uvarov’s voice. “Good. Now, Arrow Maker — look around the sky, and describe the stars you see.”

  Arrow Maker stared, beyond the ship. The spine, the Interface, were suspended in darkness.

  Uvarov’s speech became rushed, almost slurred. “Why, we might be able to place our position — and the date — by the constellations. If I can find the old catalogs; those damn survivalists in the Decks must have retained them. And — ”

  “Uvarov.” Arrow Maker tried to inject strength into his voice. “Listen to me. There’s something wrong.”

  “There can’t be. I — ”

  “There are no constellations. There are no stars.” Beyond the ship there was only emptiness; it was as if the great ship, with its flaring drive and teeming lifedome, was the only object in the Universe…

  No, that wasn’t quite true. He stared to left and right, scanning the equator of the gray-black sky around him; there seemed to be something there — a ribbon of light, too faint to make out color.

  He described this to Uvarov.

  “The starbow.” Uvarov’s voice sounded much weaker, now. “But that’s impossible. If there’s a starbow we must be traveling, still, at relativistic velocities.
But we can’t be.” The old, dead voice cracked. “Maker, you’ve seen the stars yourself.”

  “No.” Arrow Maker tried to make his voice gentle. “Uvarov, all I’ve ever seen were points of light in a sky-dome… Maybe they weren’t stars at all.”

  If, he thought ruefully, the stars ever existed at all.

  He stared at the mass of the spine as it slid upwards past him, suddenly relishing its immensity, its detail. He was glad there were no stars. If this ship was all that existed, anywhere in the Universe, then it would be enough for him. He could spend a lifetime exploring the worlds contained within its lifedome, and there would always be the forest to return to. And -

  Light filled the cabin: a storm of it, multicolored cubes and spheres which swarmed around him, dazzling him. Then, as suddenly as they had appeared, the cubes hurtled together and coalesced.

  There was a man sitting beside Arrow Maker, inside the pod, dressed in a gray silver tunic and trousers. His hands were in his lap, folded calmly, and through his belly and thighs Arrow Maker could see the quiver of arrows he’d left on the chair — he could actually see the quiver, through the flesh of the man.

  The man smiled. “My name’s Mark — Mark Bassett Friar Armonk Wu. Don’t be frightened.”

  Arrow Maker screamed.

  Lieserl swam with the photino birds through the heart of the bloated Sun. The photino birds appeared to relish Sol’s new incarnation. Plasma oscillations caused energy to flood out of the core, in neutrino-antineutrino pairs, and the birds swooped around the core, drinking in this glow of new radiance.

  The matter in the inert, collapsing core had become so compressed it was degenerate, its density so high that the intermolecular forces that governed its behavior as a gas had broken down. Now, the gravitational infall was balanced by the pressure of electrons themselves: the mysterious rule of quantum mechanics called the Pauli Exclusion Principle, which ensures that no two electrons can share the same energy level.

  But this new state of equilibrium couldn’t last for long, Lieserl realized. The shell of fusing hydrogen around the core continued to burn its way outward, raining helium ash down on the core; and so the core continued to grow, to heat up.

  Now that the inner planets were gone, she felt utterly isolated.

  Why, even the stone-faced bureaucrats of the Assimilation period had been contact of a sort. She’d found it immensely valuable to be able to share impressions with somebody else — somebody outside her own sensorium. In fact she wondered if it were possible for any human being to remain sane, given a long enough period without communication.

  But then again, she thought wryly, she wasn’t a human being…

  Into Lethe with that. She closed her eyes and stretched. She took a slow, careful inventory of her Virtual body-image. She wriggled her fingers, relishing the detailed feel of sliding tendons and stretching skin; she arched her back and felt the muscles at the front of her thighs pull taut; she worked her feet forward and back, as if she were training for some celestial ballet, and focused on the slow, smooth working of her ankles and toes.

  She was human, all right, and she was determined to stay that way — even despite the way she’d been treated by humans themselves, in her brief, but still vivid, corporeal life. What had she been but a freak, an experiment that had ultimately been abandoned?

  She didn’t owe people anything, she told herself.

  Maybe.

  But again that buried urge to communicate all this gripped her: she felt she had to tell someone about all this, to warn them.

  But those feelings weren’t logical, she knew. Since the wormhole telemetry link had been shut down she had no way to communicate anyway. And while she had dreamed, here inside the imperilled heart of the Sun, five million years had worn away in the Solar System outside. For all she knew there might be no humans left alive, anywhere, to hear whatever she might have to say.

  …Still, she itched to talk.

  Again, maser radiation shone out of a convection cell and sparkled over her, bright and coherent.

  Intrigued, she followed the path of one of the convection cells as it swept out of the heart of the Sun, bearing its freight of heat energy; she tried to trace the source of the maser light.

  The radiation, she found, was coming from a thin trace of silicon monoxide in the mantle gas. Collisions between particles were pumping the gas with energy, she saw — leaving the monoxide molecules in an unstable, excited state, rotating rapidly.

  A photon of just the right frequency, impacting a pumped molecule, could cause the molecule to tip out of its unstable state. The molecule shed energy and emitted another photon of the same frequency. So the result was two photons, where one had been before… And the two photons stimulated two more atoms, resulting in four photons… A chain reaction followed, growing geometrically, with a flood of photons from the stimulated silicon monoxide molecules — all at the same microwave frequency, and all coherent — with the same phase.

  Lieserl knew that to get significant maser effects, pumped molecules had to be arranged in a line of sight, to get a long path of coherence. The convection cells, with their huge, multimillion-mile journeys to the surface and back, provided just such pathways. Maser radiation cascaded up and down the long flanks of the cells, spearing into and out of the helium core.

  The maser radiation could even escape from the Sun altogether, she saw. The convection founts grazed the surface, at their most extreme points; maser energy was blasted out, tangential to the surface of the swollen Sun, forming tiny, precise beacons of coherent light.

  And the maser beacons were, she realized with a growing excitement, very, very distinctive.

  Excited, she swept back and forth through the huge convection cells. It wasn’t difficult, she found, to disrupt the form of the coherent silicon monoxide maser beams; she imposed structure on the beams’ polarization, phasing and coherent lengths.

  She started with simple signals: sequences of prime numbers, straightforward binary arrays of symbols. She could keep that up almost indefinitely; thanks to the time it took for the coherent radiation to reach their firing points at the surface, it was sufficient for her to return to the convection cells every few days to re-initiate her sequence of signals. She could trace echoes of her signals, in fact, persisting even in the downfalling sides of the cells.

  Then, as her confidence grew, she began to impose meaningful information content on her simple signal structure. With binary representations of images in two and three dimensions, and with data provided in every human language she knew, she began to relate the story of what had happened to her, here in the heart of the Sun — and of what the photino birds were doing to mankind’s star.

  Feverishly she worked at the maser signals, while the final death of the Sun unraveled.

  In the stern galley of the Great Britain, Louise sat before her data desks. The little pod from the lifedome showed up as a block of pixels sliding past a schematic of the Northern.

  Over the radio link she heard screams.

  “Oh, for Lethe’s sake, Mark, don’t scare him completely out of his mind.”

  Mark sounded hurt. “I’m doing my best.”

  Louise felt too tired, too used up, to cope with this sudden flood of events.

  She tried, sometimes, to remember how it had been to be young. Or even, not quite so old. It might have been different if Mark had survived, of course: his AS system had imploded after four centuries, not long after he and Louise had moved out of the lifedome and into the Britain. Maybe if Mark had lived, if she’d spent all these years with another person — not alone — she wouldn’t have ended up feeling so damn stale.

  She comforted herself with the thought that, whatever was going on today, the Northern’s immense journey was nearing its end, now. Another few decades, when she had shepherded the wormhole Interface and motley inhabitants of the lifedome — those who’d survived among those battling, swarming masses — through all these dreadful years, she would be a
ble to let go at last. Maybe she would implode then, she thought, like some dried-up husk.

  She called up a projection of its trajectory. “Well, it’s not heading for the Britain,” she told Virtual-Mark. “It’s moving past us…”

  A new voice came crackling out of her data desk now. “Arrow Maker. Arrow Maker. Listen to me. You must reach the Interface. Don’t let them stop you…”

  To Louise, this was a voice from the dead past. It was distorted by age, almost reduced to a caricature, echoing as if centuries were empty rooms.

  She localized the source of the transmission — a desk in the base of the lifedome, near the pod hangars — and she threw open a two-way link. “Uvarov? Garry Uvarov?”

  The voice fell silent, abruptly.

  She heard Mark, in the pod, saying, “Now just take it easy. I know this is strange for you, but I’m not going to hurt you.” A pause. “I couldn’t if I tried. I’ll tell you a secret: I’m not real. See? My hand is passing right through your arm, and — ”

  More screams, even shriller than before.

  Oh, Mark…

  “Come on, Uvarov,” she said. “I know it’s you. I still recognize that damn Moon accent. Speak to me.”

  “Oh, Lethe, Louise,” Mark reported, “he’s gone crazy. He’s grabbed the stick: he’s accelerating — right toward the Interface.”

  Mark was right, she saw; the craft’s speed had increased, and it was clearly heading to where the wormhole Interface was cradled in its web of superconducting hoops, bound magnetically to the structure of the GUTship.

  She punched in quick queries. Less than two minutes remained before the pod reached the Interface.

  “Uvarov, listen to me,” she said urgently. “You must respond. Please.” While she spoke her hands flew over the desks; she ordered her processors to find some way to take control of the pod. She cursed herself, silently, for her carelessness. She’d had centuries, literally, to find ways of immobilizing the lifedome pods. But she’d never imagined this scenario, some crazy savage with a painted face taking a pod into the Interface while they were still relativistic.