"Ring" - читать интересную книгу автора (Baxter Stephen)

5

Lieserl was suspended inside the body of the Sun.

She spread her arms wide and lifted up her face. She was deep within the Sun’s convective zone, the broad mantle of turbulent material beneath the glowing photosphere. Convective cells larger than the Earth, tangled with ropes of magnetic flux, filled the world around her with a complex, dynamic, three dimensional tapestry. She could hear the roar of the great gas founts, smell the stale photons diffusing out toward space from the remote core.

She felt as if she were alone in some huge cavern. Looking up she could see how the photosphere formed a glowing roof over her world perhaps fifty thousand miles above her, and the inner radiative zone was a shining, impenetrable sea another fifty thousand miles beneath her. The radiative zone was a ball of plasma which occupied eighty percent of the Sun’s diameter — with the fusing core itself buried deep within — and the convective zone was a comparatively thin layer above the plasma, with the photosphere a crust at the boundary of space. She could see huge waves crossing the surface of the radiative-zone “sea”: the waves were g-modes — gravity waves, like ocean waves on Earth — with crests thousands of miles across, and periods of days.

Lieserl? Can you hear me? Are you all right?

She thrust her arms down by her sides and swooped up into the convective-zone “air”; she looped the loop backwards, letting the floor and roof of this cavern world wheel around her. She opened up her new senses, so that she could feel the turbulence of the gas, with its almost terrestrial density, as a breeze against her skin, and the warm glow of hard photons diffusing out from the core was no more than a gentle warmth against her face.

Lieserl?

She suppressed a sigh.

“Yes. Yes, Kevan. I’m perfectly all right.”

Damn it, Lieserl, you’re going to have to respond properly. Things are difficult enough without —

“I know. I’m sorry. How are you feeling, anyway?”

Me? I’m fine. But that’s hardly the point, is it? Now come on, Lieserl, the team here are getting on my back; let’s run through the tests.

“You mean I’m not down here to enjoy myself?”

The tests, Lieserl.

“Yeah. Okay, electromagnetic first.” She adjusted her sensorium. “I’m plunged into darkness,” she said drily. “There’s very little free radiation at any frequency — perhaps an X-ray glow from the photosphere; it looks a little like a late evening sky. And — ”

Come on, Lieserl. We know the systems are functioning. I need to know what you see, what you feel.

“What I feel?”

She spread her arms and sailed backwards through the buffeting air. She opened her eyes again.

The huge semistable convection cells around her reached from the photosphere to the base of the convective zone; they buffeted against each other like living things, huge whales in this insubstantial sea of gas. And the honeycomb of activity was driven by the endless flux of energetic photons out of the radiative sea of plasma beneath her.

“I feel wonderful,” she said. “I see fountains. A cave-full of them.”

Good. Keep talking, Lieserl. You know what we’re trying to achieve here; your senses — your Virtual senses — are composites, constructs from a wide variety of inputs. I can see the individual elements are functioning; what I need to know is how well the Virtual sensorium is integrating —

“Fine.” She rolled over onto her belly, so that she was gliding face-down, surveying the plasma sea below her.

Lieserl, what now?

She adjusted her eyes once more. The flux tubes came into prominence, solidifying out of the air; beyond them the convective pattern was a sketchy framework, overlaid. “I see the magnetic flux,” she reported. “I can see what I want to see. It’s all working the way it’s supposed to, I think; I can pick out whatever feature of the world I choose, here.”

“World”?

“Yes, Kevan.” She glanced up at the photosphere, the symbolic barrier separating her forever from the Universe of humanity. “This is my world, now.”

Maybe, just don’t lose yourself down there, Lieserl.

“I won’t.”

It sounded as if there was some sympathy in his voice — knowing Kevan, there probably was; they had grown almost close in the few days she’d had left after her tour with him around the Sun.

But it was hard to tell. The communication channel linking them was a path through the wormhole, from the Interface fixed among the habitats outside the Sun to the portal which had been dropped into the Sun, and which now sustained her. The comms link was ingenious, and seemed reliable, but it wasn’t too good at relaying complex intonations.

Tell me about the flux tubes.

The tubes were each a hundred yards broad, channels of magnetic energy cutting through the air; they were thousands of miles long, and they filled the air around her, all the way down to the plasma sea.

Lieserl dipped into a tube, into its interior; she felt the tingle of enhanced magnetic strength. She lowered her head and allowed herself to soar along the length of the tube, so that its walls rushed past her, curving gracefully. “It’s terrific,” she said. “I’m in an immense tunnel; it’s like a fairground ride. I could follow this path all the way round the Sun.”

Maybe. I don’t know if we need the poetry, Lieserl. What about other tubes? Can you still see them?

“Yes.” She turned her head, and induced currents in her Virtual body made her face sparkle with radiation. “I can see hundreds, thousands of the tubes, all curving through the air — ”

The “air”?

“The convective zone gases. The other tubes are parallel with mine, more or less.” She sought for a way to convey the sensation. “I feel as if I’m sliding around the scalp of some immense giant, Kevan, following the lines of hairs.”

Scholes laughed. Well, that’s not a bad image. The flux tubes can tangle, or break, but they can’t intersect. Just like hair.

“You know, this is almost relaxing…”

Good. Again she detected that hint of sympathy — or was it pity? — in Kevan’s voice. I’m glad you’re feeling — ah — happy in yourself, Lieserl.

She let the crisp magnetic flux play over her cheeks, sharp, bright, vivid. “My new self. Well, it’s an improvement on the old; you have to admit.”

Now the flux tube curved away, consistently, to the right; she was forced to deflect to avoid crashing through the tube’s insubstantial walls.

In following the tube she became aware that she was tracing out a spiral path. She let herself relax into the motion, and watched the cave-world beyond the tube wheel around her. The flux tubes neighboring her own had become twisted into spirals, too, she realized; she was following one strand in a rope of twisted-together flux tubes.

Lieserl, what’s happening? We can see your trajectory’s altering, fast.

“I’m fine, Kevan. I’ve got myself into a rope, that’s all…”

Lieserl, you should get out of there.

She let the tube’s path sweep her around. “Why? This is fun.”

Maybe. But the rope is heading for the photosphere. It isn’t a good idea for you to break the surface; we’re concerned about the stability of the wormhole —

Lieserl sighed and let herself slow. “Oh, damn it, Kevan, you’re just no fun. I would have enjoyed bursting out through the middle of a sunspot. What a great way to go.”

Lieserl —

She slid out of the flux tube, relishing the sharp scent of the magnetic field as she cut across it. “All right, Kevan. I’m at your service. What next?”

We’re not done with the tests yet, Lieserl. I’m sorry.

“What do you want me to do?”

One more…

“Just tell me.”

Run a full self-check, Lieserl, just for a few minutes… Drop the Virtual constructs.

She hesitated. “Why? I thought you said you could tell the systems were functioning to specification, and — ”

They are. That’s not the point… We’re still testing how well integrated they are —

“Integrated into my sensorium. Why don’t you just say what you’re after, Kevan? You want to test how conscious this machine called Lieserl is. Right?”

Lieserl, you don’t need to make this difficult for me. Scholes sounded defensive. This is a standard suite of tests for any AI which —

“All right, damn it.”

She closed her eyes, and with a sudden, impulsive, stab of will, she let her Virtual image of herself — the illusion of a human body around her — crumble.

It was like — what? Like waking from a dream, a soft, comfortable dream of childhood, waking to find herself entombed in a machine, a crude construct of bolts and cords and gears.

But even that was an illusion, she thought, a metaphor for herself behind which she was hiding.

She considered herself.

The wormhole Interface was suspended in the body of the Sun. The thin, searing hot gas of the convective zone poured into its triangular faces, so that the Interface was embedded in a sculpture of inflowing gas, a flower carved dynamically from the Sun’s flesh. That material was being pumped through the wormhole to the second Interface in orbit around the Sun; there, convection zone gases emerged, blazing, making the drifting tetrahedron into a second, miniature Sun around which orbited the fragile human habitat called Thoth.

Thus the Interface refrigerated itself, enabling it to survive with its precious, fragile cargo of data stores… The stores which sustained the awareness of herself. And the flux of matter through the Interface’s planes was controlled, to enable her to move the Interface through the body of the Sun.

She inspected herself, at many levels, simultaneously.

At the physical level she studied crisp matrices of data, shifting, coalescing, the patterns of bits which, together, comprised her memories. Then, overlaid on that — visually, if she willed it, like a ghostly superstructure — was her logical level, the data storage and access paths which represented the components of her consciousness.

Good… Good, Lieserl. You’re sending us good data.

She traced paths and linkages through the interleaved and interdependent structures of her own personality. “It’s functioning well. To specification. Even beyond. I — ”

We know that. But, Lieserl, how are you feeling? That’s what we can’t tell.

“You keep asking me that, damn it. I feel — ”

Enhanced.

No longer trapped in a single point, in a box of bone a few inches behind eyes made of jelly.

She was supremely conscious.

What was her consciousness? It was the ability to be aware of what was happening in her mind, and in the world around her, and in the past.

Even in her old, battered, rapidly aging body, she had been conscious, of course. She could remember a little of what had happened to her, or in her mind, a few moments earlier.

But now, with her trace-function memory, she could relive her experiences, bit by data bit if she wanted to. Her senses went far beyond the human. And as for inner perception — why, she could see herself laid open now in a kind of dynamic blueprint.

By any test, she was more conscious than any other human had ever been — because she had more of the mechanism of consciousness. She was the most conscious human who had ever lived.

…If, she thought uneasily, I am still human.

Lieserl?

“Yes, Kevan. I can hear you.”

And?

“I’m a lot more conscious.” She laughed. “But possibly not much smarter.”

She heard him laugh in reply. It was a ghostly Virtual sound, she thought, transmitted through a defect in space-time, and — perhaps — across a boundary between species.

Come on, Lieserl. We have work to do.

She let her awareness implode, once more, into a Virtual-human form.

Her perception was immediately simplified. To be seeing through apparently human eyes was comforting… in a way. And yet, she thought, restrictive.

No wonder Superet had been so concerned to imprint her with sympathy for mankind… before it had robbed her completely of her humanity.

Perhaps it wouldn’t be much longer before she felt ready to abandon even this thin vestige of humanity.

And then what?

Bathed in Jovian light, Louise, Uvarov, Milpitas and Mark sat in the soft, reclined couches. The Virtual of Michael Poole held a snifter of old brandy; the glass was filled with convincing blue-gold Interface light sparkles, and Virtual-Poole sipped it with every sign of enjoyment — as if it were the first, and last, such glass he would ever enjoy.

As, probably, it was, for this particular autonomous sentient copy, Louise thought.

“To the survival of the species.” Louise raised her own glass and sipped at whiskey, a fine peaty Scotch. “But what’s it got to do with me? I don’t even have any kids.”

“Superet has a long history,” Virtual-Poole said stiffly. “You may not be aware of it, but Superet is already a thousand years old. It took its name from an ancient, obscure religious sect in North America that worshiped the first nuclear weapons…”

The Superet creed, in some ways, Louise thought, embodied the essence of the pre-Poole optimism of humanity. Superet believed that nothing was beyond the capabilities of mankind.

Poole gazed into his drink. “Superet believes that if something is physically possible, then it’s just a question of engineering.” The Virtual’s expression was complex — almost tormented, Louise thought. The Virtual went on, “But it takes planning — perhaps on immense timescales.”

Louise felt a vague anger build in her. Uvarov was right. This isn’t Michael Poole. Poole would not have defended the grandiose claims of Superet like this. This is a travesty of programming in conflict with sentience.

“In the past,” the Virtual went on, “Superet sponsored many of the eco engineering projects which have restored much of the biosphere of Earth — the carbon-sequestration domes, and so on.”

Louise knew that was true. The great macroengineering projects of the last millennium, supplemented by the nano-engineering of the atmosphere and lithosphere and the transfer offplanet of most power-generating and industrial concerns, had stabilized and preserved Earth’s fragile ecosystem. There was more woodland covering the temperate regions, now, than at any time since the last glaciation, locking in much of the excess carbon dioxide which had plagued previous centuries. And the great decline in species suffered after the industrialization of a couple of thousand years ago had long since been reversed, thanks to the use of genetic archives and careful reconstruction from disparate descendants — of lost genotypes.

Earth had been the first planet to be terraformed.

The Virtual said, “But Superet’s goals were modified, following the Friends of Wigner incident…”

“If Superet is such a saintly organization,” Uvarov growled, “then why is it such a thing of shadows? Why the secrets?”

Poole said, “Superet is a thousand years old, Doctor. No human organization of such longevity has ever been fully open. Think of the great established religions, societies like the Templars, the Masons. Groupings like Superet have a way of accreting tradition, and isolation, around themselves with time.”

“And,” Uvarov said sharply, “no doubt the long career of Superet has a few dark phases…”

Poole didn’t reply.

Louise said, “You said the goals of Superet were changed by the Friends incident.”

“Yes. Let me use this Virtual box of tricks to explain.”

The tetrahedron came to life again. It rotated above them, a gaudy trinket miles across.

“The Cauchy Interface,” the Virtual said. “At the time, the largest wormhole mouth constructed — in fact, the largest exercise in exotic-matter engineering.”

The Virtual’s face was gaunt in the shifting Interface light — wistful, Louise thought.

Michael Poole had been rightly celebrated for his achievements, she thought. He had been the Brunel of his day, and more. His wormhole projects had opened up the System much as the great railroads had opened up Great Britain two thousand years earlier.

A wormhole was a flaw in spacetime — a throat, connecting two events in spacetime that would otherwise be separated by light-years, or millennia. Wormholes existed naturally on all scales, most of them around the size of the Planck length — ten to minus forty three inches, the level at which space itself became granular.

Working in the orbit of Jupiter, Michael Poole and his team had taken natural wormholes and expanded them;

Poole had made wormholes big enough to permit spaceships to pass through.

Wormholes were inherently unstable. Poole had threaded his wormholes with frameworks of exotic matter — matter with negative energy density, with pressure greater than rest mass energy. The exotic matter set up repulsive gravity fields able to hold open the wormholes’ throats and mouths.

Louise remembered the excitement of those times. Poole Interfaces were towed out of Jovian orbit and set up all over the System. The wormholes enabled the inner System to be traversed in sublight GUTships in a matter of hours rather than months. The Jovian system became a hub for interplanetary commerce. Port Sol — a converted Kuiper object on the rim of the System — was established as the base for the first great interstellar voyages.

Michael Poole had opened up the Solar System in an explosion of accessibility, more dramatic than anything since the days of the great sea-going voyages of exploration on old Earth.

“It was a wonderful time. But you had greater ambitions in mind,” she said. “Didn’t you, Michael?”

The Virtual stared upwards at the display above, expression frozen, evidently unable to speak.

Mark said gently, “You mean the Cauchy, Louise?”

“Yes. Michael Poole used wormhole technology to travel — not just across space but across time.” She pointed up to the tetrahedron in the dome. “This is just one Interface from Poole’s greatest wormhole project: termini three miles across, and the throat itself no less than a mile wide. The wormhole’s second Interface was attached to a GUT-ship — the Cauchy.”

The GUTship was launched on a subrelativistic flight beyond the fringe of the Solar System — a circular tour, designed to return at last to Jupiter. The Cauchy carried one of Poole’s wormhole Interfaces with it. The other was left in orbit around Jupiter.

The flight lasted fifteen centuries — but thanks to time dilation effects, only two subjective centuries had passed for the Cauchy’s crew.

The two Interfaces remained linked by the wormhole flaw. Because of the link, when it returned to the Solar System more than a millennium into the future of the System it had left, the Cauchy’s Interface was still connected to its twin in orbit around Jupiter — where only two centuries had passed since the departure of the Cauchy, as they had for the Cauchy’s crew.

“By passing through the wormhole,” Louise said, “it was possible to travel back and forth through time. Thus, Poole had used wormhole technology to establish a bridge across fifteen hundred years, to the future.”

Mark pulled at his lips. “We all know what became of this great time bridge. But — I’ve never understood — why did Poole build it?”

The Virtual spoke, his voice tired, dry — so familiar that Louise felt her heart move. Michael Poole said, “It was an experiment. I was more interested in proving the technology — the concepts — than in the final application. But — ”

“Yes, Michael?” Louise prompted.

“I had a vision — a dream perhaps — of establishing great wormhole highways across time, as well as across space. If the technology is possible, why not? What power might be afforded to the human species with the opening up of such information channels?”

“But the future didn’t welcome this great dream,” Uvarov said drily.

“No, it didn’t,” Virtual-Poole said.

The floor of the Hermit Crab’s lifedome turned transparent; space-darkness washed across it in a sudden flood that made Milpitas gasp audibly.

Louise stood and looked down. There was space-emptiness beyond her feet; her eyes told her she was suspended above an immense drop, and she had to summon all her will not to stumble, weakly, back to her chair…

And then, belatedly, she registered what she was seeing: beneath the lifedome, and extending for hundreds of yards in every direction, was a floor of some broken, irregular, bloody material — a floor of (what looked like, but couldn’t possibly be) flesh.

Louise turned slowly around, trying to make out the geometry of what she was seeing.

The flesh-surface, bathed in sickly Jovian light, curved away from her in all directions; the “floor” was actually the outer surface of a sphere — as if the Crab were embedded in an impossible moon of flesh, perhaps a mile wide. If the Crab’s drive section still existed, it was buried somewhere deep inside this immense carcass. The clean metal lines of the GUTship’s spine — which connected lifedome to drive unit — were enveloped in a gaping wound in this floor of flesh.

Apart from this huge wound in the fleshy floor caused by the Crab (a wound which pooled with what looked un-nervingly like blood) there were a number of pockmarks in which metal glistened — weapons emplacements? — and others… eyes, huge, dimmed analogues of her own eyeballs.

There was a sense of suffering here, she thought: of pain, on an immense scale the agony of a wounded god.

She peered more closely at the nearest pockmark, trying to make out the nature of the device embedded there. But the image was little more than a sketch — a suggestion of form, rendered in shining chrome.

Virtual-Poole, with Mark, Uvarov and Milpitas, stood beside her. The Virtual studied the flesh landscape somberly. “The wormhole route to the future became a channel for invasion — by the Qax, an extraSolar species which had occupied the System by the time the bridge was established. You’re seeing here a reconstruction of one of the two Qax warships which came back through the wormhole. These are Spline — living creatures, perhaps even sentient — a technology unlike anything we’ve developed.”

Uvarov pointed to the sketchy surface of the Spline. “Your reconstruction isn’t so impressive.”

Virtual-Poole seemed more composed now, Louise thought — more Virtual, less Poole. She felt grateful for that. He said, “We know little about the Spline, save their name and gross form. I — Poole — with the help of the rebel humans from the occupation future, destroyed the invading Spline ships.” He peered down at the Crab’s spine, the huge, disrupted epidermis. “You can see how I — how he — rammed one of the warships, spearing it with the Crab’s GUTdrive. The warship was disabled — but not destroyed; in fact it was possible to take over some of the warship’s higher functions.

“I’m going to show you a reconstruction of the last few minutes of Michael Poole’s known existence.”

The sky-blue light around them started to shift, to slide over the equipment desks. Louise looked up. The Interface above the ship was moving gracefully across the sky; one triangular face, three miles wide, opened up -

— and, like some immense mouth, descended toward them.

Serena Milpitas said, “Lethe. We’re going through it, aren’t we? We’re going into the future.”

Louise looked at Poole. The Virtual gazed upwards, his eyes hardening with memory. “I drove the Spline into the wormhole. The wormhole had to be destroyed — the bridge to the future closed… That was my only goal.”

The triangular frame passed around the bulk of the Spline warship now; the lifedome shuddered — delicately, but convincingly. Blue-white flashes erupted all around the perimeter of the lifedome — damage inflicted on the flesh of the Spline, Louise guessed, by grazing collisions with the exotic-matter framework.

Suddenly they were inside the tetrahedral Interface — and the wormhole itself opened up before them. It was a tunnel, above the lifedome, delineated by sheets of autumn-gold light — and leading (impossibly) beyond the Interface framework, and arcing to infinity.

Louise wished she could touch Poole. This copy was closer to Michael Poole than any cloned twin; he shared Poole’s memories, his consciousness even. How must it be to relive one’s death like this?

Poole said, “The flashes in the wormhole throat represent the decay of heavy particles, produced in turn by the relaxing of shear energy in the curved spacetime walls of the wormhole, which — ”

Uvarov growled, “Skip the fairground ride; just tell us what happened. How did Poole destroy the wormhole?”

The Virtual turned his face toward Louise, his strong, aged features outlined by shuddering wormhole light. “The Spline ships had a hyperdrive, of unknown nature. I opened up my captive hyperdrive here — ”

The Virtual raised his hands.

The floor bucked beneath them. The wormhole was flooded with sheets of blue white light which raced toward them and down past the lifedome, giving Louise the sudden impression of huge, uncontrolled speed.

Poole shouted, “However the hyperdrive works, it must be based on manipulating the multidimensionality of space. And if so — and if it were operated inside a wormhole, where spacetime is already distorted…”

Now the sheets of light gathered into threads, sinuous snakes of luminosity which curved around the GUTship, sundering the spacetime walls.

Mark said, “So the hyperdrive made the wormhole collapse?”

“Perhaps. Or — ” Virtual-Poole lifted his simulated head to the storm of wormhole light.

The threads of light seemed to sink into the fabric of the wormhole itself. Defects — cracks and sheets — opened up in the wormhole walls, revealing a plethora of wormhole tunnels, a hydra-like explosion of ballooning wormholes.

The Hermit Crab, uncontrolled, plunged down one wormhole after another into the future.

The Crab, at last, came to Virtual rest.

The last wormhole mouth closed behind it, the stresses of its distorted spacetime fabric finally yielding in a gush of heavy particles.

The sky beyond the lifedome was dark — almost empty, save for a random scattering of dimmed, reddened stars. There was no sign of life: no large-scale structure, no purposeful motion.

The sudden flood of darkness was startling. Louise, looking up, shivered; she had a feeling of intense age. “Michael — you surely expected to die, in the destruction of the wormhole.”

“Yes… but as you can see — perhaps — the wormhole didn’t simply collapse.” He looked confused. “I’m a simulacrum, Louise; I don’t share these memories with Poole… But there is evidence. Some of the particles which emerged from the collapsing Interface, in our own time, were of much too high energies to have been generated in the collapse of a single wormhole.

“We think the impact actually created — or at any rate widened — more, branching wormholes, which carried the Crab further into the future. Perhaps much further.

“We have simulations which show how this could happen, given the right form of hyperdrive physics — particularly if there were other cross-time wormholes already extant in the Solar System of the occupation era — perhaps set up by the Qax. In fact, the assumption that the branching did occur is allowing us to rule out classes of hyperdrive theory…”

The Virtual stood, and paced slowly across the transparent floor. “I was determined to close off the time bridge — to remove the threat of invasions from the future. But — I have to tell you — Superet thinks this was a mistake.” The Virtual twisted his hands together. “After all, we had already beaten off one Spline incursion. After Poole’s departure the study of the Qax incident became the prime focus of Superet. But because the wormhole is closed, Superet is reduced to inferring the truth about the future of our species from fragments, from indirect shards of evidence…”

Louise said, “You don’t believe it was a mistake, Michael.”

Poole looked haunted; again, Louise realized with an inner ache, his personality was conflicting with the programming imposed on it by Superet.

Mark peered up at the dying stars. “So. Did Poole survive?”

Louise said, “I’d like to think he did. Even just for a short while, so that he could understand what he saw.”

Milpitas lay back in her couch and stared up at the scattering of dim, reddened stars. “I’m no cosmologist… but those stars look so old. How far in time did he come?”

The Virtual did not reply.

Uvarov said, “Why have you shown us all this? What do you want?”

Virtual-Poole raised his thin arms to the desolate sky. “Look around you, Uvarov. Perhaps this is the end of time; it is certainly the end of the stars, of baryonic life. Perhaps there are other life forms out there, not perceived by us — creatures of dark matter, the non baryonic stuff which makes up nine-tenths of the Universe. But — where is man? In fact there’s no evidence of life at all here, human or otherwise.

“Superet has pieced together some fragments of the history of the future, from the rubble the Crab left behind. We know about the Xeelee, for example. We even know — we think — the name of the Xeelee’s greatest project: the Ring. But — what happens to us? What happens to the human species? What destroys us, even as it extinguishes the stars?

“And — Superet asks — is there anything we can do to avert this, the final catastrophe?”

Louise looked up at the dying stars. “Ah. I think I understand why I’m here. Superet wants me to follow the Hermit Crab. To take the Great Northern — not to Tau Ceti — but on a circular trip, like Poole’s Cauchy, to establish a time bridge. Superet wants to set up a way — a stable way — of reaching this era: the end of time.

“I get it. We’ve long since taken responsibility for the management of our planets — for the survival of their ecologies. Why, now, should we not take responsibility for our own long term survival as a species?” She felt like laughing. “Superet really does think big, doesn’t it?”

Milpitas sat on the edge of her couch. “But what does survival mean, on such timescales? Surely even with AS treatments, survival of individuals — of us into the indefinite future is impossible. What, then? Survival of the genotype? Or of the culture of our species — the memes, the cultural elements, perhaps, preserved in some form — ”

Uvarov looked fascinated now, Louise thought; all his impatience and irritability gone, he stared up at the Virtual rendition of the future hungrily. “Either, or both, perhaps. Speaking as a flesh-and-blood human, I share a natural human bias to the survival of the actual genotype in some form. The preservation of mere information appears a sterile option to me.

“But, whatever survival means, it doesn’t matter. Look beyond the dome. In this time to which Michael Poole traveled, nothing of us has survived, in any form. And that’s the catastrophe Superet is determined — clearly — we must work to avert.”

Louise pulled her lip. “If this is such a compelling case, why is Superet a small, covert operation? Why shouldn’t Superet’s goals motivate the primary activity of the race?”

Poole sighed. “Because the case isn’t so compelling. Obviously. Louise, as a species we aren’t used to thinking on such timescales. Not yet. There is talk of hubris: of comparisons with the Friends of Wigner, who came back through time evidently — to manipulate history, to avert the Qax occupation.” He looked at Louise wearily. “There isn’t even agreement about what you’re seeing here. I’ve shown you just one scenario, reconstructed from the Interface incident evidence. Maybe, it’s argued, we’re addressing problems that don’t really exist.”

Louise folded her arms. “And what if that’s true?”

Uvarov said, “But if there’s even the smallest chance that this interpretation is correct — then isn’t it worth some investment, against the possibility?”

Mark frowned. “So we use the Northern to fly to the future. The flight to Tau Ceti is only supposed to take a century.”

Poole nodded. “With modem technology, the flight of the Northern into the future should last no more than a thousand subjective years — ”

Mark laughed. “Poole, that’s impossible. No ship could last that long, physically. No closed ecology could survive. A closed society would tear itself apart… We don’t even know if AS treatment can keep humans alive over such periods.”

Louise stared up at the simulated stars. A thousand years? Mark was right; it was inhumanly long — but she had the feeling it wasn’t long enough…

Uvarov nodded. “But that is clearly why you have been chosen: Louise, the best engineer of the day, and with will enough to sustain immense projects. You, Mark Wu, a good social engineer — ”

“There are better ones,” Mark said.

“Not married to Louise.”

“Formerly married.”

Poole turned to Milpitas. “The proposal is that you, Serena, will make the Great Northern herself viable for its unprecedented thousand-year flight. And you, Dr. Uvarov, have a deep understanding of the strengths and limitations of the engineering of the human form; you will help Mark Wu keep the people — the species — alive.”

Louise saw Uvarov’s eyes gleam.

“I’ve no intention of going on this flight,” Mark said. “And besides, the Northern already has a ship’s engineer. And a damn doctor, come to that.”

Poole smiled. “Not for this mission.”

“Hold it,” Louise said. “There’s something missing.” She thought over what she had to say: relativistic math, done in the head, was chancy. But still… “Poole, a thousand-year trip can’t be long enough.” She looked up at the decaying stars. “I’m no cosmologist. But I see no Main Sequence stars up there at all. I’d guess we’re looking at a sky from far into the future — tens of billions of years, at least.”

Poole shook his head. His Virtual face was difficult to see in the faded starlight. “No, Louise. You’re wrong. A thousand-subjective-year trip is quite sufficient.”

“How can it be?”

“Because the sky you’re seeing isn’t from tens of billions of years hence. It’s from five million years ahead. That’s all — five megayears, nothing in cosmological time…”

“But how — ”

“More than time will ruin the stars, Louise. If this reconstruction is anything like accurate, there’s an agency at large — which must be acting even now systematically destroying the stars…

“And, as a consequence, us.”

Uvarov turned his face, expressionless, up to the darkling sky.

Virtual-Poole said, “We have reason to believe that even our own Sun is subject to this mysterious assault.” He stood before Louise. “Look, Louise, you know I don’t advocate cosmic engineering — I was the one who opposed the Friends of Wigner, who did my damnedest to close my own bridge to the future. But this is different. Even I can sympathize with what Superet is attempting here. Now can you see why they want you to follow the Crab?”

The light show began to fade from the dome; evidently the display was over.

Poole still stood before Louise, but his definition was fading, his outlines growing blocky in clouds of pixels. She reached out a hand to him, but his face had already grown smooth, empty; long before the final pixels of his image dispersed, she realized, all trace of consciousness had fled.

Lieserl soared through her convective cavern, letting her sensory range expand and contract, almost at random.

She thought about the Sun.

For all its grandeur, the Sun, as a machine, was simple. When she looked down and opened her eyes she could see evidence of the fusing core, a glow of neutrino light beneath the radiative plasma ocean. If that core were ever extinguished, then the flood of energetic photons out of the core and into the radiative and convective layers would be staunched. The Sun was in hydrostatic equilibrium — the radiation pressure from the photons balanced the Sun’s tendency to collapse inwards, under gravity. And if the radiation pressure were removed the outer layers would implode, falling freely, within a few hours.

The Sun hadn’t always been as stable as this… and it wouldn’t always remain so.

The Sun had formed from a contracting cloud of gas — a protostar. At first the soft-edged, amorphous body had shone by the conversion of its gravitational energy alone.

When the central temperature had reached ten million degrees, hydrogen fusion had begun in the core.

The shrinkage had been halted, and stability reached rapidly. The fusion was restricted to an inner core, surrounded by the plasma sea and the convective “atmosphere”. The Sun, stable, burning tranquilly, had become a Main Sequence star; by the time Lieserl entered the convective zone, the Sun had burned for five billion years.

But the Sun would not remain on the Main Sequence forever.

The mass converted to energy was millions of tons per second. The Sun’s bulk was so huge that this was a tiny fraction; in all its five-billion-year history so far the Sun had burned only five percent of its hydrogen fuel…

But, relentlessly, the fuel in the core would be exhausted. Gradually an ash of helium would accumulate in the core, and the central temperature would drop. The delicate balance between gravity and radiation pressure would be lost, and the core would implode under the weight of the surrounding, cooler layers.

Paradoxically, the implosion would cause the core temperature to rise once more — so much so that new fusion processes would become possible — and the star’s overall energy output would rise.

The outer layers would expand enormously, driven out by the new-burning core. The Sun would engulf Mercury, and perhaps more of the inner planets, before reaching a new gravity-pressure equilibrium — as a red giant. This hundred million-year phase would be spectacular, with the Sun’s luminosity increasing by a factor of a thousand.

But this profligate expansion was not sustainable. Complex elements would be burned with increasing desperation in the expanding, clinker-ridden core, until at last all the available fuel was exhausted.

As the core’s temperature suddenly fell, equilibrium would be lost with sudden abandon. The Sun would implode once more, seeking a new stability. Finally, as a white dwarf, the Sun would consist of little more than its own dead core, its density a million times higher than before, with further contraction opposed by the pressure of high-speed electrons in its interior.

Slowly, the remnant would cool, at last becoming a black dwarf, surrounded — as if by betrayed children — by the charred husks of its planets.

…At least, Lieserl thought, that was the theory.

If the laws of physics were allowed to unravel, following their own logic unimpeded, the Sun’s red giant stage was still billions of years away… not mere millions of years, as Superet’s evidence suggested was the case.

Lieserl’s brief was to find out what was damaging the Sun.

Lieserl. Try to pick up the p-modes; we want to see if that sensory mechanism works…

“Absolutely. Helioseismology, here I come,” she said flippantly.

She opened her eyes once more.

A new pattern was built up by her processors, a fresh overlay on top of the images of convective cells and tangled flux tubes: gradually, she made out a structure of ghostly-blue walls and spinning planes that propagated through the convective cavern. These were p-modes: sound waves, pressure pulses fleeing through the Solar gas from explosive events like the destruction of granules on the surface. The waves were trapped in the convective layer, reflected from the vacuum beyond the photosphere and bent away from the core by the increasing sound speed in the interior. The waves canceled and reinforced each other until only standing waves survived, modes of vibration which matched the geometry of the convective cavern.

The modes filled the space around her with ghostly, spinning patterns; their character varied as she surveyed the depth of the cavern, with length scales increasing as she looked into the interior. Looking up with her enhanced vision Lieserl could see how patches — thousands of miles wide — of the Sun’s surface oscillated as the waves struck, with displacements of fifty miles and speeds of half a mile a second.

The Sun rang, like a bell.

Good… good. This is terrific data, Lieserl.

“I’m glad to oblige,” she said drily.

All right. Now let’s try putting it together. Use the neutrino flux, such as it is, and the helioseismology data, and everything else you’ve got… Let’s find out how much we can see.

Lieserl felt a thrill of excitement — subtle, but real — as she began to comply. Now she was moving to the core of her mission, even of her life: to look into the heart of the Sun, as no human had done before.

As the processors worked to integrate the data she called up from her long-term memory a template: the Standard Model of the Sun. The processors overlaid the cavern around her with yet another level of complexity, as they populated it with icons, graphics, grid lines and alphanumeric labels, showing her the basic properties of the Standard Model. The Model — refined and revised over millennia — represented humanity’s best understanding of how the Sun worked. She looked in toward the core and saw how, according to the Model, the pressure and temperature rose smoothly toward the core; the temperature graph showed as a complex three-dimensional sphere in pink and red, reaching an intensely scarlet fifteen million degrees at the very heart.

Slowly, her processors plotted the reality — as she perceived it now — against the theory; graphs and schematics blossomed over each other like clusters of multicolored flowers.

After a few minutes, her vision stabilized. She stared around at the complex imagery filling the cavern, zooming in on particular aspects, highlighting differences.

Oh, no, Scholes said. No. Something’s wrong.

“What?”

The discrepancies, Lieserl. Particularly toward the core. This simply can’t be right.

She felt amused. “You’ve gone to all the trouble of constructing me, of sending me in here like this, and now that I’m here you’re going to disbelieve what I tell you?”

But look at the divergences from the Model, Lieserl. Under a command from Scholes, the actual and predicted temperature gradients were picked out in glowing, radiant pinks. Look at this.

“Hmm…”

According to the Standard Model, the temperature should have fallen quite rapidly away from the fusion region — down by a full twenty percent from the central value after a tenth of the Sun’s radius. But in fact, the temperature drop was much more shallow… falling only a few percent, Lieserl saw, over more than a quarter of the radius.

“That’s not so surprising. Is it?” In riposte she superimposed a graphic of her own, a variant of the Standard Model. “Look at this. Here’s a model with a dark matter component — photinos, orbiting the core.” The dark matter — fast-moving, almost intangible particles kept clustered around the heart of the Sun by its gravity field — transferred energy out of the core and to the surrounding layers. “See? The photinos just leak kinetic energy — heat energy — out of the core. The central temperature is suppressed, and the core is made isothermal uniform temperature — out to about ten percent of the radius.”

Scholes sounded testy, impatient. Yes, he said, but what we’re looking at here is an isothermal region covering three times that radius — twenty-five times the volume predicted even by the widest of the Standard Model’s variants. It’s impossible, Lieserl. Something must be going wrong with —

“With what? With the eyes you’ve built for me? Or with your own expectations?”

Irritated, she canceled all the schematics. The spheres and contour lines imploded in sparkles of pixels, exposing the native panorama of the convective cavern, a complex, ghostly overlay of flux tubes, p-modes and convection cells.

Frustrated, with some analogue of nervous energy building in her, she sent her Virtual self soaring around the cavern. She chased the rotating p-wave modes, sliced through flux tubes. “Kevan. What if the effect we’re seeing is real? Maybe this divergence in the core is what you’ve sent me in here to find.”

Maybe… Lieserl, what will you do next?

“It’s early days, but I think I’ll soon have learned all I can out here.”

Out here?

“In the cavern — the convective zone. All the evidence we have is indirect, Kevan. The real action is deeper in, at the core.”

But you can’t go any deeper, Lieserl. Your design… the wormhole will implode if you try to penetrate the radiative zone…

“Maybe. Well, it’s up to you to sort that out, Kevan.”

She swooped up to the glowing roof of the cavern, and plunged down, at hundreds of miles a second, toward the plasma sea, past the slow-pulsing flanks of giant p-modes.