Ring

1

Even at the moment she was born she knew something was wrong.

A face loomed over her: wide, smooth, smiling. The cheeks were damp, the glistening eyes huge. “Lieserl. Oh, Lieserl…”

Lieserl. My name, then.

She explored the face before her, studying the lines around the eyes, the humorous upturn of the mouth, the strong nose. It was an intelligent, lived-in face. This is a good human being, she thought. Good stock…

“Good stock?”

This was impossible. She was impossible. She felt terrified of her own explosive consciousness. She shouldn’t even be able to focus her eyes yet…

She tried to touch her mother’s face. Her own hand was still moist with amniotic fluid — but it was growing visibly, the bones extending and broadening, filling out the loose skin as if it were a glove.

She opened her mouth. It was dry, her gums already sore with budding teeth.

Strong arms reached beneath her; bony adult fingers dug into the aching flesh of her back. She could sense other adults surrounding her, the bed in which she’d been born, the outlines of a room.

Her mother held her high before a window. Lieserl’s head lolled, the expanding muscles still too weak to support the burgeoning weight of her skull. Spittle laced across her chin.

An immense light flooded her eyes.

She cried out.

Her mother enfolded her in her arms. “The Sun, Lieserl. The Sun…”

The first few days were the worst.

Her parents — impossibly tall, looming figures — took her through brightly lit rooms, a garden always flooded with sunlight. She learned to sit up. The muscles in her back fanned out, pulsing as they grew. To distract her from the unending pain, clowns tumbled over the grass before her, chortling through huge red lips, before popping out of existence in clouds of pixels.

She grew explosively, feeding all the time, a million impressions crowding into her soft sensorium.

There seemed to be no limit to the number of rooms in this place, this House. Slowly she began to understand that some of the rooms were Virtual chambers — blank screens against which any number of images could be projected. But even so, the House must comprise hundreds of rooms. And she — with her parents wasn’t alone here. There were other people. But at first they kept away, out of sight, apparent only by their actions: the meals they prepared, the toys they left her.

On the third day her parents took her on a trip by flitter. It was the first time she’d been away from the House, its grounds. As the flitter rose she stared through the bulbous windows, pressing her nose to heated glass.

The House was a jumble of white, cube-shaped buildings, linked by corridors and surrounded by garden — grass, trees. Further out there were bridges and roads looping through the air above the ground, more houses like a child’s bricks sprinkled across glowing hillsides.

The flitter soared higher.

The journey was an arc over a toylike landscape. A breast of blue ocean curved away from the land, all around her. This was the island of Skiros, Phillida — her mother — told her, and the sea was called the Aegean. The House was the largest construct on the island. She could see huge, brown-painted spheres dotting the heart of the island: carbon-sequestration domes, Phillida said, balls of dry ice four hundred yards tall.

The flitter snuggled at last against a grassy sward close to the shore of the ocean. Lieserl’s mother lifted her out and placed her — on her stretching, unsteady legs — on the rough, sandy grass.

Hand in hand, the little family walked down a short slope to the beach.

The Sun burned from an unbearably blue sky. Her vision seemed telescopic. She looked at distant groups of children and adults playing — far away, halfway to the horizon — and it was as if she was among them herself. Her feet, still uncertain, pressed into gritty, moist sand.

She found mussels clinging to a ruined pier. She prized them away with a toy spade, and gazed, fascinated, at their slime-dripping feet. She could taste the brine salt on the air; it seemed to permeate her very skin.

She sat on the sand with her parents, feeling her light costume stretch over her still-spreading limbs. They played a simple game, of counters moving over a floating Virtual board, with pictures of ladders and hissing snakes. There was laughter, mock complaints by her father, elaborate pantomimes of cheating.

Her senses were electric. It was a wonderful day, full of light and joy, extraordinarily vivid sensations. Her parents loved her — she could see that in the way they moved with each other, came to her, played with her.

They must know she was different; but they didn’t seem to care.

She didn’t want to be different — to be wrong. She closed her mind against her fears, and concentrated on the snakes, the ladders, the sparkling counters.

Every morning she woke up in a bed that felt too small.

Lieserl liked the garden. She liked to watch the flowers straining their tiny, pretty faces toward the Sun, as the great light climbed patiently across the sky. The sunlight made the flowers grow, her father told her. Maybe she was like a flower, she thought, growing too quickly in all this sunlight.

The House was full of toys: colorful blocks, and puzzles, and dolls. She picked them up and turned them over in her stretching, growing hands. She rapidly became bored with each toy, but one little gadget held her attention. It was a tiny village immersed in a globe of water. There were tiny people in there, frozen in mid-step as they walked, or ran, through their world. When her awkward hands shook the globe, plastic snowflakes would swirl through the air, settling over the encased streets and rooftops. She stared at the entombed villagers, wishing she could become one of them: become frozen in time as they were, free of this pressure of growing.

On the fifth day she was taken to a wide, irregularly shaped, sunlight drenched classroom. This room was full of children — other children! The children sat on the floor and played with paints and dolls, or talked earnestly to brilliantly colored Virtual figures — smiling birds, tiny clowns.

The children turned to watch as she came in with her mother, their faces round and bright, like dapples of sunlight through leaves. She’d never been so close to other children before. Were these children different too?

One small girl scowled at her, and Lieserl quailed against her mother’s legs. But Phillida’s familiar warm hands pressed into her back. “Go ahead. It’s all right.”

As she stared at the unknown girl’s scowling face, Lieserl’s questions, her too-adult, too-sophisticated doubts, seemed to evaporate. Suddenly, all that mattered to her — all that mattered in the world — was that she should be accepted by these children: that they wouldn’t know she was different.

An adult approached her: a man, young, thin, his features bland with youth. He wore a jumpsuit colored a ludicrous orange; in the sunlight, the glow of it shone up over his chin. He smiled at her. “Lieserl, isn’t it? My name’s Paul. We’re glad you’re here. Aren’t we, people?”

He was answered by a rehearsed, chorused “Yes”.

“Now come and we’ll find something for you to do,” Paul said. He led her across the child-littered floor to a space beside a small boy. The boy — red haired, with startling blue eyes — was staring at a Virtual puppet which endlessly formed and reformed: the figure two, collapsing into two snowflakes, two swans, two dancing children; the figure three, followed by three bears, three fish swimming in the air, three cakes. The boy mouthed the numbers, following the tinny voice of the Virtual. “Two. One. Two and one is three.”

Paul introduced her to the boy — Tommy — and she sat down with him. Tommy, she was relieved to find, was so fascinated by his Virtual that he scarcely seemed aware that Lieserl was present — let alone different.

Tommy was resting on his stomach, his chin cupped in his palms. Lieserl, awkwardly, copied his posture.

The number Virtual ran through its cycle. “Bye bye, Tommy! Goodbye, Lieserl!” It winked out of existence.

Now Tommy turned to her — without appraisal, merely looking, with unconscious acceptance.

Lieserl said, “Can we see that again?”

He yawned and stuck a finger into one nostril. “No. Let’s see another. There’s a great one about the pre-Cambrian explosion — ”

“The what?”

He waved a hand dismissively. “You know, the Burgess Shale and all that. Wait till you see Hallucigenia crawling over your neck…”

The children played, and learned, and napped. Later, the girl who’d scowled at Lieserl — Ginnie — started some trouble. She poked fun at the way Lieserl’s bony wrists stuck out of her sleeves (Lieserl’s growth rate was slowing, but she was still expanding out of her clothes each day). Then — unexpectedly, astonishingly — Ginnie started to bawl, claiming that Lieserl had walked through her Virtual. When Paul came over Lieserl started to explain, calmly and rationally, that Ginnie must be mistaken; but Paul told her not to cause such distress, and for punishment she was forced to sit away from the other children for ten minutes, without stimulation.

It was all desperately, savagely unfair. It was the longest ten minutes of Lieserl’s life. She glowered at Ginnie, filled with resentment.

The next day she found herself looking forward to going to the room with the children again. She set off with her mother through sunlit corridors. They reached the room Lieserl remembered — there was Paul, smiling a little wistfully to her, and Tommy, and the girl Ginnie — but Ginnie seemed different: childlike, unformed…

At least a head shorter than Lieserl.

Lieserl tried to recapture that delicious enmity of the day before, but it vanished even as she conjured it. Ginnie was just a kid.

She felt as if something had been stolen from her.

Her mother squeezed her hand. “Come on. Let’s find a new room for you to play in.”

Every day was unique. Every day Lieserl spent in a new place, with new people.

The world glowed with sunlight. Shining points trailed endlessly across the sky: low-orbit habitats and comet nuclei, tethered for power and fuel. People walked through a sea of information, with access to the Virtual libraries available anywhere in the world, at a subvocalized command. The landscapes were drenched with sentience; it was practically impossible to get lost, or be hurt, or even to become bored.

On the ninth day Lieserl studied herself in a Virtual holomirror. She had the image turn around, so she could see the shape of her skull, the lie of her hair. There was still some childish softness in her face, she thought, but the woman inside her was emerging already, as if her childhood was a receding tide. She would look like Phillida in the strong-nosed set of her face, her large, vulnerable eyes; but she would have the sandy coloring of her father, George.

Lieserl looked about nine years old. But she was just nine days old.

She bade the Virtual break up; it shattered into a million tiny, fly-sized images of her face which drifted away in the sunlit air.

Phillida and George were fine parents, she thought. They were physicists; and they both belonged to an organization they called “Superet”. They spent their time away from her working through technical papers — which scrolled through the air like falling leaves — and exploring elaborate, onion-ring Virtual models of stars. Although they were both clearly busy, they gave themselves to her without hesitation. She moved in a happy world of smiles, sympathy and support.

Her parents loved her unreservedly. But that wasn’t always enough.

She started to come up with complicated, detailed questions. Like, what was the mechanism by which she was growing so rapidly? She didn’t seem to eat more than the other children she encountered; what could be fuelling her absurd growth rate?

How did she know so much? She’d been born self-aware, with even the rudiments of language in her head. The Virtuals she interacted with in the classrooms were fun, and she always seemed to learn something new; but she absorbed no more than scraps of knowledge through the Virtuals compared to the feast of insight with which she awoke each morning.

What had taught her, in the womb? What was teaching her now?

The strange little family had worked up some simple, homely rituals together. Lieserl’s favorite was the game, each evening, of snakes and ladders. George brought home an old set — a real board made of card, and wooden counters. Already Lieserl was too old for the game; but she loved the company of her parents, her father’s elaborate jokes, the simple challenge of the game, the feel of the worn, antique counters.

Phillida showed her how to use Virtuals to produce her own game boards. Her first efforts, on her eleventh day, were plain, neat forms, little more than copies of the commercial boards she’d seen. But soon she began to experiment. She drew a huge board of a million squares. It covered a whole room — she could walk through the board, a planar sheet of light at about waist height. She crammed the board with intricate, curling snakes, vast ladders, vibrantly glowing squares — detail piled on detail.

The next morning she walked with eagerness to the room where she’d built her board — and was immediately disappointed. Her efforts seemed pale, static, derivative: obviously the work of a child, despite the assistance of the Virtual software.

She wiped the board clean, leaving a grid of pale squares floating in the air. Then she started to populate it again — but this time with animated half-human snakes, slithering “ladders” of a hundred forms. She’d learned to access the Virtual libraries, and she plundered the art and history of a hundred centuries to populate her board.

Of course it was no longer possible to play games on the board, but that didn’t matter. The board was the thing, a world in itself. She withdrew a little from her parents, spending long hours in deep searches through the libraries. She gave up her daily classes. Her parents didn’t seem to mind; they came to speak to her regularly, and showed an interest in her projects, but they respected her privacy.

The board kept her interest the next day. But now she evolved elaborate games, dividing the board into countries and empires with arbitrary bands of glowing light. Armies of ladder-folk joined with legions of snakes in crude recreations of the great events of human history.

She watched the symbols flicker across the Virtual board, shimmering, coalescing; she dictated lengthy chronicles of the histories of her imaginary countries.

By the end of the day, though, she was starting to grow more interested in the history texts she was consulting than in her own elaborations on them. She went to bed, eager for the next morning to come.

She awoke in darkness, doubled in agony.

She called for light. She sat up in bed.

Blood spotted the sheets. She screamed.

Phillida sat with her, cradling her head. Lieserl pressed herself against her mother’s warmth, trying to still her trembling.

“I think it’s time you asked me your questions.”

Lieserl sniffed. “What questions?”

“The ones you’ve carried around with you since the moment you were born.” Phillida smiled. “I could see it in your eyes, even at that moment. You poor thing… to be burdened with so much awareness. I’m sorry, Lieserl.”

Lieserl pulled away. Suddenly she felt cold, vulnerable. “Who am I, Phillida?”

“You’re my daughter.” Phillida placed her hands on Lieserl’s shoulders and pushed her face close; Lieserl could feel the warmth of her breath, and the soft room light caught the gray in her mother’s blond hair, making it shine. “Never forget that. You’re as human as I am. But — ” She hesitated.

“But what?”

“But you’re being — engineered.

“There are nanobots in your body,” Phillida said. “Do you understand what a nanobot is? A machine at the molecular level which — ”

“I know what a nanobot is,” Lieserl snapped. “I know all about AntiSenescence and nanobots. I’m not a child, Mother.”

“Of course not,” Phillida said seriously. “But in your case, my darling, the nanobots have been programmed — not to reverse aging — but to accelerate it. Do you understand?”

Nanobots swarmed through Lieserl’s body. They plated calcium over her bones, stimulated the generation of new cells, forced her body to sprout like some absurd human sunflower — they even implanted memories, artificial learning, directly into her cortex.

Lieserl felt like scraping at her skin, gouging out this artificial infection. “Why? Why did you let this be done to me?”

Phillida pulled her close, but Lieserl stayed stiff, resisting mutely. Phillida buried her face in Lieserl’s hair; Lieserl felt the soft weight of her mother’s cheek on the crown of her head. “Not yet,” Phillida said. “Not yet. A few more days, my love. That’s all…”

Phillida’s cheeks grew warmer, as if she were crying, silently, into her daughter’s hair.

Lieserl returned to her snakes and ladders board. She found herself looking on her creation with affection, but also nostalgic sadness; she felt distant from this elaborate, slightly obsessive concoction.

Already she’d outgrown it.

She walked into the middle of the sparkling board and bade a Sun, a foot wide, rise out from the center of her body. Light swamped the board, shattering it.

She wasn’t the only adolescent who had constructed fantasy worlds like this. She read about the Brontes, in their lonely parsonage in the north of England, and their elaborate shared world of kings and princes and empires. And she read about the history of the humble game of snakes and ladders. The game had come from India, where it was a morality teaching aid called Moksha-Patamu. There were twelve vices and four virtues, and the objective was to get to Nirvana. It was easier to fail than to succeed… The British in the nineteenth century had adopted the game as an instructional guide for children called Kismet; Lieserl stared at images of claustrophobic boards, forbidding snakes. Thirteen snakes and eight ladders showed children that if they were good and obedient their life would be rewarded.

But by a few decades later the game had lost its moral subtexts. Lieserl found images from the early twentieth century of a sad-looking little clown who clambered heroically up ladders and slithered haplessly down snakes.

The game, with its charm and simplicity, had survived through the twenty centuries which had worn away since the death of that forgotten clown. Lieserl stared at him, trying to understand the appeal of his baggy trousers, walking cane and little moustache.

She grew interested in the numbers embedded in the various versions of the game. The twelve-to-four ratio of Moksha-Patamu clearly made it a harder game to win than Kismet’s thirteen-to-eight — but how much harder?

She began to draw new boards in the air. But these boards were abstractions clean, colorless, little more than sketches. She ran through high-speed simulated games, studying their outcomes. She experimented with ratios of snakes to ladders, with their placement. Phillida sat with her and introduced her to combinatorial mathematics, the theory of games — to different forms of wonder.

On her fifteenth day she tired of her own company and started to attend classes again. She found the perceptions of others a refreshing counterpoint to her own, high-speed learning.

The world seemed to open up around her like a flower; it was a world full of sunlight, of endless avenues of information, of stimulating people.

She read up on nanobots. She learned the secret of Anti-Senescence, the process which had rendered humans effectively immortal.

Body cells were programmed to commit suicide.

Left alone, a cell manufactured enzymes which cut its own DNA into neat pieces, and quietly closed itself down. The suicide of cells was a guard against uncontrolled growth — tumors — and a tool to sculpt the developing body: in the womb, for example, the withering of unwanted cells carved fingers and toes from blunt tissue buds.

Death was the default state of a cell. Chemical signals had to be sent out by the body, to instruct cells to remain alive. It was a dead-man’s-switch control mechanism: if cells grew out of control — or if they separated from their parent organ and wandered through the body — the reassuring environment of chemical signals would be lost, and they would be forced to die.

The nanotechnological manipulation of this process made AntiSenescence simple.

It also made simple the manufacture of a Lieserl.

Lieserl studied this, scratching absently at her inhabited, engineered arms.

She looked up the word Superet in the Virtual libraries. She had access to no reference to it. She wasn’t an expert at data mining, but she thought there was a hole here.

Information about Superet was being kept from her.

With a boy called Matthew, from her class, she took a trip away from the House without her parents, for the first time. They rode a flitter to the shore where she’d played as a child, twelve days earlier. She found the broken pier where she’d discovered mussels. The place seemed less vivid — less magical — and she felt a sad nostalgia for the loss of the freshness of her childish senses. She wondered why no adult ever commented on this dreadful loss of acuity. Perhaps they just forgot, she thought.

But there were other compensations.

Her body was strong, lithe, and the sunlight was like warm oil on her skin. She ran and swam, relishing the sparkle of the ozone-laden air in her lungs. She and Matthew mock-wrestled and chased in the surf, clambering over each other like children, she thought, but not quite with complete innocence.

As sunset approached they allowed the flitter to return them to the House. They agreed to meet the next day, perhaps take another trip somewhere. Matthew kissed her lightly, on the lips, as they parted.

That night she could barely sleep. She lay in the dark of her room, the scent of salt still strong in her nostrils, the image of Matthew alive in her mind. Her body seemed to pulse with hot blood, with its endless, continuing growth.

The next day — her sixteenth — Lieserl rose quickly. She’d never felt so alive; her skin still glowed from the salt and sunlight of the shore, and there was a hot tension inside her, an ache deep in her belly, a tightness.

When she reached the flitter bay at the front of the House, Matthew was waiting for her. His back was turned, the low sunlight causing the fine hairs at the base of his neck to glow.

He turned to face her.

He reached out to her, uncertainly, then allowed his hands to drop to his sides. He didn’t seem to know what to say; his posture changed, subtly, his shoulders slumping slightly; before her eyes he was becoming shy of her.

She was taller than him. Visibly older. She became abruptly aware of the still childlike roundness of his face, the awkwardness of his manner. The thought of touching him — the memory of her feverish dreams during the night — seemed absurd, impossibly adolescent.

She felt the muscles in her neck tighten; she felt as if she must scream. Matthew seemed to recede from her, as if she were viewing him through a tunnel.

Once again the laboring nanobots — the vicious, unceasing technological infection of her body — had taken away part of her life.

This time, though, it was too much to bear.

Phillida had never looked so old. Her skin seemed drawn tight across the bones of her face, the lines etched deep. “I’m sorry,” she said. “Believe me. When we — George and I — volunteered for Superet’s program, we knew it would be painful. But we never dreamed how much. Neither of us had children before. Perhaps if we had, we’d have been able to anticipate how this would feel.”

“I’m a freak — an absurd experiment,” Lieserl shouted. “A construct. Why did you make me human? Why not some insentient animal? Why not a Virtual?”

“Oh, you had to be human. As human as possible…”

“I’m human in fragments,” Lieserl said bitterly. “In shards. Which are taken away from me as soon as they’re found. That’s not humanity, Phillida. It’s grotesque.”

“I know. I’m sorry, my love. Come with me.”

“Where?”

“Outside. To the garden. I want to show you something.”

Suspicious, hostile, Lieserl allowed her mother to take her hand; but she made her fingers lie lifeless, cold in Phillida’s warm grasp.

It was mid-morning now. The Sun’s light flooded the garden; flowers — white and yellow — strained up toward the sky.

Lieserl looked around; the garden was empty. “What am I supposed to be seeing?”

Phillida, solemnly, pointed upwards.

Lieserl tilted back her head, shading her eyes to block out the Sun. The sky was a searing-blue dome, marked only by a high vapour trail and the lights of orbital habitats.

Gently, Phillida pulled Lieserl’s hand down from her face, and, cupping her chin, tipped her face flower-like toward the Sun.

The star’s light seemed to fill her head. Dazzled, she dropped her eyes and stared at Phillida through a haze of blurred, streaked retinal images. “The Sun?”

“Lieserl, you were — constructed. You know that. You’re being forced through a human lifecycle at hundreds of times the normal pace — ”

“A year every day.”

“Approximately, yes. But there is a purpose, Lieserl. A justification. You aren’t simply an experiment. You have a mission.” She waved her hand at the sprawling, friendly buildings that comprised the House. “Most of the people here, particularly the children, don’t know anything about you, Lieserl. They have jobs, goals — lives of their own to follow. But they’re here for you.

“Lieserl, the House is here to imprint you with humanity. Your experiences have been designed — George and I were selected, even — to ensure that the first few days of your existence would be as human as possible.”

“The first few days?” Suddenly the unknowable future was like a black wall, looming toward her; she felt as out of control of her life as if she were a counter on some immense, invisible snakes-and-ladders board. She lifted her face to the warmth of the Sun. “What am I?”

“You are… artificial, Lieserl.

“In a few weeks your human shell will become old. You’ll be transferred into a new form… Your human body will be — ”

“Discarded?”

“Lieserl, it’s so difficult. That moment will seem like a death to me. But it won’t be death. It will be a metamorphosis. You’ll have new powers — even your awareness will be reconstructed. Lieserl, you’ll become the most conscious entity in the Solar System…”

“I don’t want that. I want to be me. I want my freedom, Phillida.”

“No, Lieserl. You’re not free, I’m afraid; you never can be. You have a goal.”

“What goal?”

Phillida lifted her face to the Sun once more. “The Sun gave us life. Without it — without the other stars — we couldn’t survive.

“We’re a strong species. We believe we can live as long as the stars — for tens of billions of years. And perhaps even beyond that… If we’re allowed to. But we’ve had — glimpses — of the future, the far distant future. Disturbing glimpses.

“People are starting to plan, to assure we’re granted our destiny. People are working on projects which will take millions of years to come to fruition… People like those working for Superet.

“Lieserl, you’re one of those projects.”

“I don’t understand.”

Phillida took her hand, squeezed it gently; the simple human contact seemed incongruous, the garden around them transient, a chimera, before this talk of megayears and the future of the species.

“Lieserl, something is wrong with the Sun. You have to find out what. The Sun is dying; something — or someone — is killing it.” Phillida’s eyes were huge before her, staring, probing for understanding. “Don’t be afraid. My dear, you will live forever. If you want to. And you will see wonders which I can only dream of.”

Lieserl stared into her mother’s huge, weak eyes. “But you don’t envy me. Do you, Phillida?”

“No,” Phillida said quietly.

2

Louise Ye Armonk stood on the weather deck of the SS Great Britain. From here she could see the full length of Brunel’s fine steam liner: the polished deck, the skylights, the airy masts with their loops of wire rigging, the single, squat funnel amidships.

And beyond the glowing dome which sheltered the old ship, the sky of the Solar System’s rim loomed like a huge, empty room.

Louise still felt a little drunk — sourly now — from the orbiting party she’d left a few minutes earlier. She subvocalized a command to send nanobots scouring through her bloodstream; she sobered up fast, with a brief shudder.

Mark Bassett Friar Armonk Wu — Louise’s ex-husband — stood close by her. They’d left the Great Northern, with its party still in full swing, to come here, to the surface of Port Sol, in a cramped pod. Mark was dressed in a one-piece jumpsuit of some pastel fabric; the lines of his neck were long and elegant as he turned his head to survey the old ship.

Louise was glad they were alone, that none of the Northern’s prospective interstellar colonists had decided to follow them down for a last few moments on this outpost of Sol, to reminisce with this fragment of Earth’s past — even though reminiscence was part of the reason Louise had had the old ship brought out here in the first place.

Mark touched her arm; his palm, through the thin fabric of her sleeve, felt warm, alive. “You’re not happy, are you? Even at a moment like this. Your greatest triumph.”

She searched his face, seeking out his meaning. He wore his hair shaven, so that his fine, fragile-looking skull showed through his dark skin; his nose was sharp, his lips thin, and his blue eyes — striking in that dark face — were surrounded by a mesh of wrinkles. He’d once told her he’d thought of getting the wrinkles smoothed out — it would be easy enough in the course of AS-renewal but she’d campaigned against it. Not that she’d have cared too much, but it would have taken most of the character out of that elegant face — most of its patina of time, she thought.

“I never could read you,” she said at last. “Maybe that’s why we failed in the end.”

He laughed lightly, a sparkle of intoxication still in his voice. “Oh, come on. We lasted twenty years. That’s not a failure.”

“In a lifetime of two hundred years?” She shook her head. “Look. You ask me about my feelings. Anyone who didn’t know you — us — would think you cared. So why do I think that, in some part of your head, you’re laughing at me?”

Mark drew his hand away from her arm, and she could almost see the shutters coming down behind his eyes. “Because you’re an ill tempered, morose, graceless — oh, into Lethe with it.”

“Anyway, you’re right,” Louise said at last.

“What?”

“I’m not happy. Although I’m not sure I could tell you why.”

Mark smiled; the sourceless light of the Britain’s dome smoothed away the lines around his eyes. “Well, if we’re being honest with each other for once, I do kind of enjoy seeing you suffer. Just a bit. But I care as well. Come on, let’s walk.”

He took her arm again, and they walked along the ship’s starboard side. The soles of their shoes made soft sucking sounds as the shoes’ limited processors made the soles adhere to and release the deck surface, unobtrusively reinforcing Port Sol’s microgravity. The shoes almost got it right; Louise felt herself stumble only a couple of times.

Around the ship was a dome of semisentient glass, and beyond the dome — beyond the pool of sourceless light which bathed the liner — the landscape of Port Sol stretched to its close-crowding horizon. Port Sol was a hundred-mile ball of friable rock and water-ice, with traces of hydrogen, helium and a few hydrocarbons. It was like a huge comet nucleus. Port Sol’s truncated landscape was filled with insubstantial, gossamer forms: sculptures raised from the ancient ice by natural forces reduced to geological slowness by the immense distance of the Sun.

Port Sol was a Kuiper object. With uncounted companions, it circled the Sun beyond the orbit of Pluto, shepherded there by resonances of the major planets’ gravitational fields.

Louise looked back at the Great Britain. Even against the faery background of Port Sol, still Brunel’s ship struck her as a thing of lightness, grace and elegance. She remembered going to see the ship in her dry dock on Earth; now, as then, she compressed her eyes, squinting, trying to make out the form of the thing — the Platonic ideal within the iron, which poor old Isambard had tried to make real. The ship was three thousand tons of iron and wood, but with her slim, sharp curves and fine detail she was like a craft out of fantasy. Louise thought of the gilded decorations and the coat-of-arms figurehead around the stern, and the simple, affecting symbols of Victorian industry carved into the bow: the coil of rope, the cogwheels, the set-square, the wheat-sheaf. It was impossible to imagine such a delicate thing braving the storms of the Atlantic…

She tilted back her head, and looked for the brightish star in Capricorn that was Sol, all of four billion miles away. Surely even a visionary like old Isambard never imagined that his first great ship would make her final voyage across such an immense sea as this.

Mark and Louise climbed down a steep staircase amidships to the promenade deck; they strolled along the deck past blocks of tiny cabins toward the engine-room bulkhead.

Mark ran a fingertip over the surface of a cabin wall as they passed. He frowned, rubbing his fingertips together. “The surface feels odd… not much like wood.”

“It’s preserved. Within a thin shell of semisentient plastic, which seals it, nourishes it… Mark, the damn boat was launched in 1843. Over two thousand years ago. There wouldn’t be much left of her without preservation. Anyway, I thought you weren’t interested.”

He sniffed. “Not really. I’m more interested in why you wanted to come down here: now, in the middle of all the celebrations for the completion of the starship.”

“I try to avoid introspection,” she said heavily.

“Oh, sure.” He turned to her, his face picking up the soft glow of the ancient wood. “Talk to me, Louise. The bit of me that cares about you is outvoting the bit that enjoys seeing you suffer, just for the moment.”

She shrugged. She couldn’t help sounding sour. “You tell me. You always were good at diagnosing the condition of the inside of my head. At great and tedious length. Maybe I’m feeling melancholy after completing my work on the Northern. Could that be it, do you think? Maybe I’m going through some equivalent of a post-coital depression.”

He snorted. “With you, it was post, pre and during, frankly. No, I don’t think it’s that… And besides,” he said slowly, “your work on the Northern isn’t finished yet. You’re planning to leave with her. Aren’t you? Spend subjective decades hauling her out to Tau Ceti.”

She heard herself growl. “How did you find out about that? No wonder you drove me crazy, all those years. You’re too damn interested in me.”

“I’m right, though, aren’t I?”

Now they reached the Britain’s dining room. It was a fantastic Victorian dream. Twelve columns of white and gold, with ornamental capitals, ran down its spine, and the room was lined by two sets of twelve more columns each. Doorways between the columns led off to passageways and bedrooms, and the door archways were gilded and surmounted by medallion heads. The walls were lemon-yellow, relieved by blue, white and gold; omnipresent, sourceless light shone from the cutlery and glassware on the three long tables.

Mark walked across the carpet and ran his hand over a table’s gleaming, polished surface. “You should do something about this semisentient plastic: have it give the surfaces some semblance of their natural texture. The touch is half the beauty of a thing, Louise. But you always were… remote, weren’t you? Happy enough with the surface of things — with their look, their outer form. Never interested in touching, in getting closer.”

She ignored that. “Brunel had a lot of style, you know. He worked on a tunnel under the Thames, with his father.”

“Where?” Mark had been born in Port Cassini, Titan.

“The Thames. A river, in England… on Earth. The tunnel was flooded, several times. Once, when it had been pumped out, Brunel threw a dinner party right up against the working face for fifty people. He got the band of the Coldstream Guards to — ”

“Hmm. How interesting,” Mark said dryly. “Maybe you should put some food on these tables. Why not? It could be preserved, by your sentient plastic. You could have segments of dead animals. As devoured by the great Brunel himself.”

“You never did have any taste, Mark.”

“I don’t think your mood has anything to do with the completion of the Northern.”

“Then what?”

He sighed. “It’s you, of course. It always is. For a long time, while we were together, I thought I understood your motivation. There would always be another huge, beautiful GUTship to build; another immense undertaking to lose yourself in. And since we’re all immortal now, thanks to AntiSenescence, I thought that would be enough for you.

“But I was wrong. It isn’t like that. Not really.”

Louise was aware of intense discomfort, somewhere deep within her; she felt she wanted to talk, read a bookslate, bury herself in a Virtual — anything to drown out his words.

“You always were smarter than me, Mark.”

“In some ways, yes.”

“Just say what you’ve got to say, and get it over.”

“You want immortality, Louise. But not the dreary literal immortality of AS — not just a body-scouring every few years — but the kind of immortality attained by your idols.” He waved a hand. “By Brunel, for instance. By achieving something unique, wonderful. And you fear you’ll never be able to, no matter how many starships you build.”

“You’re damn patronizing,” she snapped. “The Northern is a great achievement.”

“I know it is. I’m not denying it.” He smiled, triumph in his eyes. “But I’m right, aren’t I?”

She felt deflated. “You know you are. Damn you.” She rubbed her eyes. “It’s the shadow of the future, Mark…”

A century and a half earlier, the future had invaded the Solar System.

It had been humanity’s own fault; everyone recognized that. Under the leadership of an engineer called Michael Poole the Interface project — a wormhole link to a future a millennium and a half ahead — had been completed.

At the time Louise Ye Armonk was well established in her chosen field of GUTship engineering… at least, as established as any mere fifty-year-old could be, in a society increasingly dominated by the AS-preserved giants of the recent past. Louise had even worked, briefly, with Michael Poole himself.

Why had Poole’s wormhole time link been built? There were endless justifications — what power could a glimpse of the future afford? — but the truth was, Louise knew, that it had been built for little more than the sheer joy of it.

The Interface project came at the end of centuries of expansion for mankind. The Solar System had been opened up, first by GUTdrive vessels and later by wormhole links, and the first GUTdrive starship fuelling port — Port Sol — was already operational.

It was difficult now to recapture the mood of those times, Louise thought. Confidence — arrogance… The anthropic theories of cosmological evolution were somewhere near their paradigmatic peak. Some people believed humans were alone in the Universe. Others even believed the Universe had been designed, by some offstage agency, with the sole object of delivering and supporting humans. Given time, humans would do anything, go anywhere, achieve whatever they liked.

But Poole’s Interface had been a bridge to the real future.

The incident that followed the opening of the wormhole had been confused, chaotic, difficult to disentangle. But it had been a war — brief, spectacular, like no battle fought in Solar space before or since, but a war nevertheless.

Future Earth — at the other end of Poole’s time bridge, a millennium and a half hence — would be under occupation, by an alien species about whom nothing was known save their name: Qax.

Rebel humans from the occupation era were pursued back through time, through Poole’s Interface, by two immense Qax warships. The rebels, with the help of Michael Poole, had destroyed the warships. Then Poole had driven a captured warship into the Interface wormhole, to seal it against further invasion — and in the process Poole himself was lost in time. The rebels, stranded in their past, had fled the Solar System in a captured GUTdrive ship, evidently intending to use time dilation effects to erode away the years back to their own era.

The System, stunned, slowly recovered.

Various bodies — like the Holy Superet Light Church — still, after a hundred and fifty years, combed through the fragments of data from the Interface incident, trying to answer the unanswerable.

Like: what had truly happened to Michael Poole?

It was known that the Qax occupation itself would eventually be lifted, and humanity would resume its expansion — but now more warily, and into a Universe known to be populated by hostile competitors…

A Universe containing, above all, the Xeelee. And it was said that before Poole’s wormhole path to the future finally closed, some information had been obtained on the far future — of millions of years hence, far beyond the era of the Qax. Louise could see how some such data could be obtained — by the flux of high-energy particles from the mouth of the collapsing wormhole, for instance.

And the rumors said that the far future — and what it held for mankind — were bleak indeed.

Louise and Mark stood on the forecastle deck and looked up toward the Sun.

The Great Northern, Louise’s GUTdrive starship, passed serenely over their heads, following its stately, four-hour orbit through the Kuiper object’s shallow gravitational well. The Northern’s three-mile-long spine, encrusted with sensors, looked as if it had been carved from glass. The GUTdrive was embedded in a block of Port Sol ice, a silvery, irregular mass at one end of the spine. The lifedome — itself a mile across — was a skull of glass, fixed to the spine’s other end. Lights shone from the lifedome, green and blue; the dome looked like a bowlful of Earth, here on the rim of the System.

“It’s beautiful,” Mark said. “Like a Virtual. It’s hard to believe it’s real.” The light from the Britain’s dome under-lit his face, throwing the fine lines around his mouth into relief. “And it’s a good name, Louise. Great Northern. Your starship will head out where every direction is north — away from the Sun.”

Staring up at the shimmering Northern now, Louise remembered Virtual journeys through ghostly, stillborn craft: craft which had evolved around her as the design software responded to her thoughts. How Brunel would have thrived with modern software, which once again enabled the vision of individuals to dominate such huge engineering projects. And some of those lost ships had been far more elegant and daring than the final design — which had been, as ever, a compromise between vision and economics.

…And that was the trouble. The real thing was always a disappointment.

“Louise, you shouldn’t fear the future,” Mark said.

Instantly Louise was irritated. “I don’t fear it,” she said. “Lethe, don’t you even understand that? It’s Michael Poole and his damn Interface incident. I don’t fear the future. The trouble is, I know it.”

“We all do, Louise,” Mark said, his patience starting to sound a little strained. “And most of us don’t let it affect us — ”

“Oh, really. Look at yourself, Mark. What about your hair, for instance? — or rather, your lack of it.”

Mark ran a self-conscious hand up and over his scalp.

She went on, “Everyone knows that this modern passion for baldness comes from those weird human rebels from the future, the Friends of Wigner. So you can’t tell me you’re not influenced by knowing what’s to come. Your very hairstyle is a statement of — ”

“All right,” he snapped. “All right, you’ve made your point. You never know when to shut up, do you? But, Louise — the difference is we aren’t all obsessed by the future. Unlike you.”

He walked away from her, his gait stiff with annoyance.

They climbed down into the engine room. Multicolored light filtered down through an immense skylight. Four inclined cylinders thrust up from the floor of the ship; the pistons stood idle like the limbs of iron giants, and a vast chain girdled the drive machinery.

Louise rubbed her chin and stared at the machinery. “Obsessed? Mark, the future contains the Xeelee — godlike entities so aloof from us that we may never understand what they are trying to achieve — and with technology, with engineering, like magic. They have a hyperdrive.” She let her voice soften. “Do you understand what that means? It means that somewhere in the Universe, now, the damn Xeelee are riding around in FTL chariots which make my poor Northern look like a horse-drawn cart.

“And we believe they have an intraSystem engine — their so-called discontinuity drive — which powers night-dark ships with wings like sycamore leaves, hundreds of miles wide…

“I’m not denying my GUTdrive module is a beautiful piece of engineering. I’m proud of it. But compared to what we understand of Xeelee technology, Mark, it’s — it’s a damn steam engine. Why, we even use ice as reaction mass. Think of that! What’s the point of building something which I know is outdated before I even start?”

Mark laid a hand on her shoulder and squeezed. His touch was warm, firm, and as he’d no doubt intended — disconcertingly intimate. “So that’s why you’re running away.”

“I’d hardly call leaving on a one-way colonizing expedition to Tau Ceti ‘running away’.”

“Of course it is. Here is where you can achieve things — here, with the resources of a Solar System. You’re an engineer, damn it. What will you build on some planet of Tau Ceti? A real steam engine, maybe.”

“But — ” She struggled to find words that didn’t sound, even to her, like self justifying whines. “But maybe that would count for more, in the greater scheme of things, even than a dozen bigger and better Northerns. Do you see?”

“Not really.” His voice sounded flat, tired; perhaps he was letting himself sober up.

They stood for a while, in a silence broken only by their breathing. Then he said, “I’m sorry, Louise. I’m sorry you’re letting such moods spoil your night of triumph. But I’ve had enough; I feel as if I’ve been listening to that stuff for half my life.”

As usual when his mood turned like this, she was filled with regret. She tried to cover his hand, which still lay on her shoulder. “Mark — ”

He slid his hand away. “I’m going back to the pod, and up to the ship, and I’m going to get a little more drunk. Do you want to come?”

She thought about it. “No. Send the pod down again. Some of the cabins here are made up; I can — ”

There was a sparkling in the air before him. She stumbled back, disconcerted; Mark moved closer to her to watch.

Pixels — thumbnail cubes of light — tumbled over each other, casting glittering highlights from Brunel’s ancient machinery. They coalesced abruptly into the lifesize, semi-transparent Virtual image of a human head: round, bald, cheerful. The face split into a grin. “Louise. Sorry to disturb you.”

“Gillibrand. What in Lethe do you want? I thought you’d be unconscious by now.”

Sam Gillibrand, forty going on a hundred and fifty, was Louise’s chief assistant. “I was. But my nanobots were hooked up to the comms panel; they sobered me up fast when the message came in. Damn them.” Gillibrand looked cheerful enough. “Oh, well; I’ll just have it all to do again, and — ”

“The comms panel? What was the message, Sam?”

Gillibrand’s grin became uncertain. “City Hall. There’s been a change to the flight plan.” Gillibrand’s voice was high, heavily accented mid-American, and not really capable of conveying much drama. And yet Louise felt herself shudder when Gillibrand said: “We’re not going to Tau Ceti after all.”

3

The old woman leaned forward in her seat, beside Kevan Scholes.

The surface of the Sun, barely ten thousand miles below the clear-walled cabin of the Lightrider, was a floor across the Universe. The photosphere was a landscape, encrusted by granules each large enough to swallow the Earth, and with the chromosphere — the thousand-mile-thick outer atmosphere — a thin haze above it all.

Scholes couldn’t help but stare at his companion. Her posture was stiff, and her hands — neatly folded in her lap, over her seatbelt — were gaunt, the skin peeked by liver-spots and hanging loosely from the bones. Like gloves, he thought. She wore a simple silver-gray coverall whose only decoration was a small brooch pinned to the breast. The brooch depicted a stylized snake entwined around a golden ladder.

The little ship passed over a photosphere granule; Scholes watched absently as it unfolded beneath them. Hot hydrogen welled up from the Solar interior at a speed of half a mile a second, then spread out across the photosphere surface. This particular fount of gas was perhaps a thousand miles across, and, in its photosphere-hugging orbit, the Lightrider was traveling so rapidly that it had passed over the granule in a few minutes. And Scholes saw as he looked back that the granule was already beginning to disintegrate, the hydrogen spill at its heart dwindling. Individual granules persisted less than ten minutes, on average.

“How beautiful this is,” his companion said, gazing down at the Sunscape. “And how complex — how intricate, like some immense machine, perhaps, or even a world.” She turned to him, her mouth — surrounded by its dense web of wrinkles folded tight. “I can imagine whiling away my life, just watching the slow evolutions of that surface.”

Scholes looked across the teeming Sunscape. The photosphere was a mass of ponderous motion, resembling the surface of a slowly boiling liquid. The granules, individual convective cells, were themselves grouped into loose associations: supergranules, tens of thousands of miles across, roughly bounded by thin, shifting walls of stable gas. As he watched, one granule exploded, its material bursting suddenly across the Solar surface; neighboring granules were pushed aside, so that a glowing, unstructured scar was left on the photosphere, a scar which was slowly healed by the eruption of new granules.

Scholes studied his companion. The sunlight underlit her face, deepening the lines and folds of loose flesh there. It made her look almost demonic — or like something out of a distant, unlamented past. She’d fallen silent now, watching him; some response was expected, and he sensed that his customary glib flippancy — which usually passed for conversation in the Solar habitat — wouldn’t do.

Not for her.

He summoned up a smile, with some difficulty. “Yes, it’s beautiful. But — ” Scholes had spent much of the last five years within a million miles of the Sun’s glowing surface, but even so had barely started to become accustomed to the eternal presence of the star. “It’s impossible to forget it’s there… Even when I’m in Thoth, with the walls opaqued — when I could really be anywhere in the System, I guess.” He hesitated, suddenly embarrassed; her cold, rheumy eyes were on him, analytical. “I’m sorry. I don’t know how to explain it any better.”

Was there a hint of a smile on that devastated face? “You needn’t be self conscious.”

Kevan Scholes had volunteered for this assignment — a simple three-hour orbital tour with this mysterious woman who, a few days earlier, had been brought to Thoth, the freefall habitat at the center of the wormhole project. It should have been little more than a sightseeing jaunt — and a chance to learn more about this ancient woman, and perhaps about the true goals of Superet’s wormhole project itself.

And besides, it was a break from his own work. Scholes was supervising the assembly of one vertex of a wormhole Interface from exotic matter components. When the wormhole was complete, one of its pair of tetrahedral Interfaces would be left in close orbit around the Sun. The other, packed with an ambitious AI complex, would be dropped into the Sun itself.

The work was well paid, though demanding; but it was dull, routine, lacking fulfillment. So a break was welcome… But he had not expected to be so disconcerted by this extraordinary woman.

He tried again. “You see, we’re all scientists or engineers here,” he said. “A sense of wonder isn’t a prerequisite for a job on this project — it’s probably a handicap, actually. But that’s a star out there, after all: nearly a million miles across — five light-seconds — and with the mass of three hundred thousand Earths. Even when I can’t see it, I know it’s there; it’s like a psychic pressure, perhaps.”

She nodded and turned her face to the Sun once more. “Which is why we find speculation about its destruction so extraordinarily distressing. And, of course, to some extent we are actually within the body of the Sun itself. Isn’t that true?”

“I guess so. There’s no simple definition of where the Sun ends; there’s just a fall-off of density, steep at first, then becoming less dramatic once you’re outside the photosphere… Let me show you.”

He touched his data slate, and the semisentient hull suppressed the photosphere’s glow. In its new false colors the Sunscape became suffused with deep crimsons and purples; the granules seethed like the clustering mouths of undersea volcanoes.

“My word,” she murmured. “It’s like a landscape from a medieval hell.”

“Look up,” Scholes said.

She did so, and gasped.

The chromosphere was a soft, featureless mist around the ship. And the corona the Sun’s outer atmosphere, extending many Solar diameters beyond the photosphere — was a cathedral of gas above them, easily visible now that the photosphere light was suppressed. There were ribbons, streamers of high density in that gas; it was like an immense, slow explosion all around them, expanding as if to fill space.

“There’s so much structure,” she said. She stared upwards, her watery eyes wide and unblinking. Scholes felt disquieted by her intensity. He restored the transparency of the hull, so that the corona was overwhelmed once more.

A sunspot — deep black at its heart, giving an impression of a wound in the Sun’s hide, of immense depth — unfolded beneath them, ponderously.

“We seem to be traveling so slowly,” she said.

He smiled. “We’re in free orbit around the Sun. We’re actually traveling at three hundred miles a second.”

He saw her eyes widen.

He said gently, “I know. It takes a little while to get used to the scale of the Sun. It’s not a planet. If the Earth were at the center of the Sun, the whole of the Moon’s orbit would be contained within the Sun’s bulk…”

They were directly over the spot now; its central umbra was like a wound in the Sun’s glowing flesh, deep black, with the penumbra a wide, gray bruise around it. This was the largest of a small, interconnected family of spots, Scholes saw now; they looked like splashes of paint against the photosphere, and their penumbrae were linked by causeways of grayness. The spot complex passed beneath them, a landscape wrought in shades of gray.

“It’s like a tunnel,” Lieserl said. “I imagine I can see into it, right down into the heart of the Sun.”

“That’s an illusion, I’m afraid. The spot is dark only by contrast with the surrounding regions. If a major spot complex could be cut out of the Sun and left hanging in space, it would be as bright as the full Moon, seen from Earth.”

“But still, the illusion of depth is startling.”

Now the spot complex was passing beneath them, rapidly becoming foreshortened.

Scholes said uncertainly, “Of course you understand that what you see of the Sun, here, is a false-color rendering by the hull of the Lightrider. The ’Rider’s hull is actually almost perfectly reflective. Excess heat is dumped into space with high-energy lasers fixed to the hull: the ’Rider refrigerates itself, effectively. In fact, if you could see the ship from outside it would actually be glowing more brightly than the photosphere itself…” Scholes was uncomfortably aware that he was jabbering.

“I think I follow.” She waved her claw-like hand, delicately, at the glowing surface. “But the features are real, of course. Like the spot complex.”

“Yes. Yes, of course.” Lethe, he thought suddenly. Am I patronizing her?

His brief had been to show this strange old woman the sights — to give her the VIP tour. But he knew nothing about her — it was quite possible she knew far more about the subjects he was describing than he did.

The Holy Superet Light Church was notoriously secretive: about the goals of this Solar wormhole project, and the role the old woman would play in it… although everyone knew, from the way she had been handled since arriving in near-Solar space — as if she was as fragile and precious as an eggshell — that this woman was somehow the key to the whole thing.

But how much did she know?

He watched her birdlike face carefully. The way her gray hair had been swept back into a small, hard bun made her strong-nosed face even more gaunt and threatening than it might otherwise have been.

She asked, “And is this refrigeration process how the wormhole probe is going to work — to become able to penetrate the Sun itself?”

He hesitated. “Something like it, yes. The key to refrigerating a volume is to suck heat out of the volume faster than it’s allowed in. We’ll be taking Solar heat away from the AI complex out through the wormhole, and dumping it outside the Sun itself; actually we’re planning to use that energy as a secondary power source for Thoth…”

She shifted in her chair, stiff and cautious, as if afraid of breaking something. “Dr. Scholes, tell me. Will we be leaving freefall?”

The question was surprising. He looked at her; “During this flight, in the Lightrider?”

She returned his look calmly, waiting.

“We’re actually in free orbit around the Sun; this close to the surface the period is about three hours… We’ll make a complete orbit. Then we’ll climb back out to Thoth… But we’ll proceed the whole way at low acceleration; you should barely feel a thing. Why do you ask?” He hesitated. “Are you uncomfortable?”

“No. But I would be if we started to ramp up the gees. I’m a little more fragile than I used to be, you see.” Her tone was baffling — self-deprecating, wistful, perhaps with a hint of resentment.

He nodded and turned away, unsure how to respond. “Oh, dear.” Unexpectedly, she was smiling, revealing small, yellow-gold teeth. “I’m sorry, Dr. Scholes. I suspect I’m intimidating you.”

“A little, yes.” He grinned.

“You really don’t know what to make of me, do you?”

He spread his hands. “The trouble is, frankly, I’m not sure how much you know.” He hesitated. “I don’t want to feel I’m patronizing you, by — ”

“Don’t feel that.” Unexpectedly she let her hand rest on his; her fingers felt like dried twigs, but her palm was surprisingly warm, leathery. “You’re fulfilling the request I made, for this trip, very well. Assume I know nothing; you can treat me as an empty-headed tourist.” Her smile turned into a grin, almost mischievous; suddenly she seemed much less alien, in Scholes’ eyes. “As ignorant as a visiting politician, or Superet high-up, even. Tell me about sunspots, for instance.”

He laughed. “All right… To understand that, you need to know how the Sun is put together.”

The Sun was a thing of layers, like a Chinese box.

At the Sun’s heart was an immense fusion reactor, extending across two hundred thousand miles. This core region — contained within just a quarter of the Sun’s diameter — provided nearly all the Sun’s luminosity, the energy which caused the Sun to shine.

Beyond the fusing core, the Sun consisted of a thinning plasma. Photons packets of radiation emitted from the core — worked their way through this radiative layer, on average traveling no more than an inch before bouncing off a nucleus or electron. It could take an individual photon millions of years to work its way through the crowd to the surface of the Sun.

Moving outwards from the core, the density, temperature and pressure of the plasma fell steadily, until at last — four-fifths of the way to the surface electrons could cling to nuclei to form atoms — and, unlike the bare nuclei of the plasma, the atoms were able to absorb the energy of the photons.

It was as if the photons, after struggling out from the fusing center, had hit a brick wall. All of their energy was dumped into the atoms. The gas above the wall responded — like a pan of water heated from below — by convecting, with hot material rising and dragging down cooler material from above.

The wormhole probe, with its fragile cargo, would be able to penetrate as far as the bottom of this convective zone, twenty percent of the way toward the center of the Sun.

She nodded. “And the photosphere which we see, with its granules and supergranules, is essentially the top layer of the convective zone. It’s like the surface of your pan of boiling water.”

“Yes. And it’s the properties of the material in the convective zone that cause sunspots.”

The convective zone matter was highly charged. The Sun’s magnetic field was intense, and its flux tubes, each a hundred yards across, became locked into the charged material.

The Sun’s rotation spread the frozen-in flux lines, stretching them around the Sun’s interior like bands of elastic. The tubes became tangled into ropes, disturbed by bubbles of rising gas and twisted by convection. Kinks in the tangled ropes became buoyant enough to float up to the surface and spread out, causing spots and spot groups.

She smiled as he spoke. “You know, I feel as if I’m returning to my childhood. I studied Solar physics intensely,” she said. “And a lot else, besides. I remember doing it. But…” She sighed. “I seem to retain less and less.

“The Sun is my life’s work, you see, Dr. Scholes. I’ve known that since I was born. I once knew much about the Sun. And in the future,” she went on ambiguously, “I shall once again know a great deal. More, perhaps, than anyone who has yet lived.”

He decided to be honest with her. “That doesn’t make a lot of sense.”

“No. No, I don’t suppose it does,” she said sharply. “But that doesn’t matter, Dr. Scholes. Your brief is to do just what you’ve been doing: to show me the sights, to let me feel the Sun from a human perspective.”

A human perspective?

Now she turned and looked directly into his eyes; her gaze, watery as it was, was open and disconcerting, searing. “But your curiosity about my role isn’t what’s throwing you off balance. Is it?”

“I—”

“It’s my age.” She grinned again, deliberately — it seemed to him — showing her grotesque, yellowed teeth. “I’ve seen you studying me, from the comer of your eye… Don’t worry, Kevan Scholes, I don’t take offense. My age is the subject you’ve been politely skirting since I climbed aboard this flying refrigerator of yours.”

He felt resentful. “You’re mocking me.”

She snorted. “Of course I am. But it’s the truth, isn’t it?”

He tried not to let his anger build. “What reaction do you expect?”

“Ah… honesty at last. I expect nothing less than your rather morbid fascination, of course.” She raised her hands and studied them, as if they were artifacts separate from her body; she turned them around, flexing her fingers. “How awful it is that this aging was once the lot of all of humanity, this slow disintegration into decay, physical and mental. Especially the physical, actually… My body seems to crowd out my awareness; sometimes I’ve time for nothing else but to cater to its pressing, undignified needs…” She frowned. “But perhaps AS treatment has robbed our species of rather more than it has given us. After all, even the most vain, or most attention-seeking, refuse to be AS-frozen at more than, say, physical-sixty. So meaningful interaction is restricted to a physical range of a mere six decades. How sad.”

He took a breath. “But you must be — physical-eighty?”

Her mouth twitched. “That’s not a bad guess, for someone who’s never met an old person before… unless you’ve ever encountered an unfortunate individual for whom AS treatment has failed to take. These are humans in their natural state, if you think about it, but our society treats them as ill — to be feared, shunned.”

Gently, he asked, “Is that what’s happened to you?”

“Failed AS treatments?” Her papery cheeks trembled briefly, and again he perceived resentment, a deep anger, just under her abrasive, disconcerting surface. “No. Not exactly.”

He touched her arm. “Look there… ahead of us.” There was a structure before them, looming out of the flat-infinite horizon, rising from the photosphere itself. It was like a viaduct — a series of arches, loops of crimson-glowing gas which strode across the Solar surface.

Once again he heard her gasp.

He checked his data slate. “Prominences. The whole structure is a hundred thousand miles long, twenty thousand high…” He glanced up and checked their heading. “We’re only ten thousand miles above the surface ourselves. We’re going to pass through one of those arches.”

She clapped her hands in delight, and suddenly she seemed astonishingly, unnervingly young — a child trapped in a decaying husk of a body, he thought.

Soon the arch through which they would pass was huge before them, and the mouths of the others began to close up, foreshortened. In this landscape of giants, Scholes found he had trouble visualizing the scale of the structures; their approach seemed to take forever, yet still they grew, thrusting out of the Sun like the dreams of some insane engineer. Now he could make out detail — there were places were the arch was not complete, and he could see knots of higher density in the coronal gas which flowed, glowing, down the magnetically shaped flanks toward pools of light at the feet of the arch. But despite all this the illusion of artifice persisted, making the structure still more intimidating.

At last the arch swept over them, immense, aloof, grand. “Five thousand miles thick,” he said slowly. “Just think; you could hang the Earth up there, at the apex of that arch, like a Christmas tree ornament.”

She snorted, and pressed the back of her hand to her mouth.

He looked at her curiously. She was — he realized slowly — giggling.

They passed through the arch; the vast sculpture of gas receded slowly behind them.

Scholes checked his data slate. “We’ve almost completed our orbit. Three million miles of a Solar great circle traversed in three hours…”

“So our journey’s nearly done.” She folded her hands neatly in her lap once more, and turned her face to the clear wall; corona light played around her profile, making her look remote, surprisingly young.

He felt suddenly moved by her — by this lonely, bitter woman, isolated by her age and fragility from the rest of mankind… and, he suspected obscurely, isolated by some much more dramatic secret.

He tried to reassure her. “Another hour and you’ll be safely inside the habitat. You’ll be a lot more comfortable there. And — ”

She turned to him. She wasn’t smiling, but her face seemed to have softened a little, as if she understood what he was trying to do. Again she reached out and touched the back of his hand, and the sudden human contact was electric. “Thank you for your patience, Dr. Scholes. I’ve not given you an easy time, have I?”

He frowned, troubled. “I don’t think I’ve been patient at all, actually.”

“Oh, but you have.”

His curiosity burned within him, like the Sun’s fusion core, illuminating everything he saw. “You’re at the heart of all this, aren’t you? The Superet project, I mean. I don’t understand what your role is… But that’s the truth, isn’t it?”

She said nothing, but let her hand remain on his…

He frowned. She seemed so fragile. “And how do you feel about it?”

“How do I feel?” She closed her eyes. “Do you know, I’m not sure if anyone has asked me that before. How do I feel?” She sighed, raggedly. “I’m scared, Dr. Scholes. That’s how I feel.”

He let his fingers close around hers.

There was a subtle push in the base of his spine, and the sound of the Lightrider’s drive was a deep, low vibration, a seismic rumble he felt deep within the fabric of his body.

Slowly, the little ship climbed away from the Sun’s boiling surface.

4

The flitter tumbled from the shimmering throat of the wormhole transit route from Port Sol to Earthport. Louise Ye Armonk peered out of the cramped cabin, looking for Earth. Mark sat beside her, a bookslate on his lap.

Earthport was a swarm of wormhole Interfaces clustered at L4 — one of the five gravitationally stable Lagrange points in the Earth-Moon system, leading the Moon in its orbit around Earth by sixty degrees. From here, Earth was a swollen blue disc; wormhole gates of all sizes drifted across the face of the old planet like electric-blue, tetrahedral snowflakes.

The flitter — unmanned save for its two passengers — surged unhesitatingly through the tangle of Interfaces, the mesh of traffic which passed endlessly through the great cross-System gateways. In contrast to the desolation of the outer rim, Louise received a powerful, immediate impression of bustle, prosperity, activity, here at the heart of the System.

At the flitter’s standard one-gee acceleration the final leg from L4 to Earth itself would take only six hours; and already the old planet, pregnant and green, seemed to Louise to be approaching rapidly, as if surfacing through the complex web of wormhole Interfaces. Huge fusion stations — constructed from ice moons towed into Earth orbit from the asteroid belt and beyond — sparkled as they crawled above green-blue oceans. The planet itself was laced with lights, on land and sea. In the thin rim of atmosphere near the North Pole Louise could just make out the dull purple glow of an immense radiator beam, a diffuse refrigerating laser dumping a fraction of Earth’s waste heat into the endless sink of space.

Louise felt an absurd, sentimental lump rise to her throat as she studied the slowly turning planet. At moments like this she felt impelled to make private vows about spending more time here: here, at the vital core of the System, rather than on its desolate edge.

…But, she reminded herself harshly, the rim was where the Northern was being built.

Louise had work to do. She was trying to equip a starship, damn it. She didn’t have the time or energy to hop back to Earth to play guessing games with some unseen authority.

Growling subvocally, Louise rested her head against her couch and tried to sleep. Mark, patient and placid, called a new page of his bookslate.

The little ship landed in North America, barely thirteen hours after leaving Port Sol — all of four billion miles away. The flitter brought them to a small landing pad near the heart of Central Park, New York City. Louise saw two people — a man and a woman — approaching the pad across the crisp grass.

The flitter’s autopilot told them to make their way to a small, anonymous-gray building close to the pad.

Louise and Mark emerged into the sunshine of a New York spring. Louise could see the shoulders of tall, ancient skyscrapers at the rim of the park, interlaced by darting flitters. Not far away, shielded by trees at the heart of the park, she made out one of the city’s carbon-sequestration domes. The dome was a sphere of dry ice four hundred yards tall: sequestration was an old Superet scheme, with each dome containing fifty million tons of carbon dioxide boldly frozen out of the atmosphere and lagged by a two-yard layer of rock wool.

Mark raised his face to the Sun and breathed deeply. “Mmm. Cherry blossom and freshly cut grass. I love that smell.”

Louise snorted. “Really? I didn’t know cherry trees grew wild, on Titan.”

“We have domes,” he said defensively. “Anyway, every human is allowed to be sentimental about a spring day in New York. Look at those clouds, Louise. Aren’t they beautiful?”

She looked up. The sky was laced by high, fluffy, dark clouds. And beyond the clouds she saw crawling points of light: the habitats and factories of near Earth space. It was a fine view — but quite artificial, she knew. Even the clouds were fakes: they were doped with detergent, to limit the growth of the water droplets which comprised them. Smaller droplets reflected more sunlight than larger ones, making the semi-permanent clouds an effective shield against excessive Solar heating.

So much for sentiment. Everything was manufactured.

Louise dropped her head. As always on returning to Earth, she felt disoriented by the openness of the sky above her — it seemed to counter every intuition to have to believe that a thin layer of blue air could protect her adequately from the rigours of space.

“Come on,” she said to Mark. “Let’s get this over with.”

Following the instructions of the autopilot they approached the nearby building. The structure was brick-shaped, perhaps ten feet tall; there was a low doorway in the center of its nearest face.

As they got closer, the two people Louise had noticed from the air walked slowly toward them from the rear of the building.

The two parties stared at each other curiously.

The man stepped forward, his hands behind his back. He was thin and tall, physical-fifty, with a bald, pallid scalp fringed by white hair. He stared frankly at Louise. “I know your face,” he said.

Louise let her eyebrows lift. “Really? And you are — ”

“My name is Uvarov. Garry Benson Deng Uvarov.” He held out his hand; his voice had the flat, colorless intonation of the old Lunar colonies, Louise thought. “My field is eugenics. And my companion — ” He indicated the woman, who came forward. “This is Serena Milpitas.”

The woman grinned. She was plump but strong-looking, about physical-forty, with short-cropped hair. “That’s Serena Harvey Gallium Harvey Milpitas,” she said. “And I’m an engineer.”

Uvarov gazed at Louise, his eyes a startling blue. “It’s very pleasant to meet you, Louise Ye Armonk. I’ve followed the construction of your starship with interest. But I am a busy man. I’ll be very pleased to learn why you’ve summoned us here.”

“Me too,” Milpitas growled. She had the lazy, nasal pitch of a Martian.

Louise felt confused. “Why I summoned you… ?”

Mark stepped forward and introduced himself. “I think you’ve got it wrong, Dr. Uvarov. We don’t know any more than you do, it seems. We were summoned too.”

Louise stared at Uvarov, feeling an immediate dislike for the man gather in her heart. “Yeah. And I bet we had further to come than you, too.”

Mark looked sour. “First blood to you, Louise. Well done. Come on; the only way we’re all going to get away from here is to go through with this, it seems.”

Striding confidently, he led the way toward the low building.

Studying each other suspiciously, the rest followed.

Louise passed through the squat, open doorway — and was plunged immediately into the darkness of space.

She heard Mark gasp; he stopped a pace behind her, his step faltering. She turned to him. He’d raised his head to a darkened dome above them; a sliver of salmon-pink (Jovian?) cloud slid across the lip of the dome, casting a light across his face, a light which softened the shadows of his apparent age. She reached out and found his hand; it was thin, cold. “Don’t let it get to you,” she whispered. “It’s just a stunt. A Virtual trick, designed to put us off balance.”

He pulled his hand away from hers; his fingernails scratched her palm lightly. “I know that. Lethe, you’ll never learn to stop patronizing me, will you?”

She thought of apologizing, then decided to skip it.

Uvarov walked forward briskly — hoping, it seemed, to catch the Virtual projectors of this illusion off guard. But the chamber moved past him fluidly, convincingly, shadows and hidden aspects unfolding with seamless grace.

The four of them were in a dome, a half-sphere a hundred yards across. At the geometric center of the dome were tipped-back control couches. A series of basic data entry and retrieval desks clustered around the couches. The rest of the floor area was divided by shoulder-high partitions into lab areas, a galley, a gym, a sleeping area and shower. The shower was enclosed by a spherical balloon of some clear material — obviously designed for zero-gee operation, Louise thought.

The sleeping zone contained a single sleep pouch. There was a noticeable absence of decoration — of any real sign of personality, Louise thought. There was no concession to comfort — no sign of entertainment areas, for example. Even the gym was functional, bare, little more than an open coffin surrounded by pneumatic weight-simulators. The only color in the chamber came from the screens of the data desks, and from the slice of Jovian cloud visible through the dome.

Serena Milpitas strolled toward Louise, her footsteps clicking loudly on the hard floor. She ran a fingertip along the surface of a data desk. “It’s a high quality Virtual projection, with semisentient surface backup,” she said. “Feel it.”

“I don’t need to,” Louise groused. “I’m sure it is. That’s not the bloody point. This is obviously meant to be the life-dome of a GUTship — a small, limited, primitive design compared to my Northern, but a GUTship nevertheless. And — ”

Light, electric-blue, flooded the dome. The explosion of brilliance was overwhelming, drenching; Louise couldn’t help but cower. Her own shadow — sharp, black, utterly artificial — seemed to peer up at her, mocking her.

She lifted her head. Beyond the transparent dome above her, an artifact — a tetrahedron glowing sky-blue — sailed past the limb of the Jovian planet. It was a framework of glowing rods: at first sight the framework looked open, but Louise could make out glimmers of elusive, brown-gold membranes of light stretched across the open faces. Those membranes held tantalizing images of starfields, of suns that had never shone over Jupiter.

“A wormhole Interface,” Milpitas breathed.

“Obviously,” Uvarov said. “So we’re in a Virtual GUTship, sailing toward an Interface in orbit around Jupiter.” He turned to Louise, letting his exasperation show. “Haven’t you got it yet?” He waved a hand. “The meaning of this ludicrous stunt?”

Louise smiled. “We’re in the Hermit Crab, aren’t we? On Michael Poole’s ship.”

“Yes. Just before it flew into Poole’s Interface — just before Poole got himself killed.”

“Not quite.”

The new voice came from the control couches at the heart of the lifedome. Now one of the couches spun around, slowly, and a man climbed out gracelessly. He walked toward them, emerging into the glaring blue overhead light of the Interface. He said, “Actually we don’t know if Poole was killed or not. He was certainly lost. He may still be alive — although it’s difficult to say what meaning words like ‘still’ have when spacetime flaws spanning centuries are traversed.”

The man smiled. He was thin, tired-looking, with physical age around sixty, Louise supposed; he wore a drab one-piece coverall.

The face — the clothes — were startling in their familiarity to Louise; a hundred memories crowded, unwelcome, for her attention.

“I know you,” she said slowly. “I remember you; I worked with you. But you were lost in time…”

“My name,” the man said, “is Michael Poole.”

Lieserl wanted to die.

It was her ninetieth day of life, and she was ninety physical-years old. She was impossibly frail — unable to walk, or feed herself, or even clean herself. The faceless men and women tending her had almost left the download too late, she thought with derision; they’d already had one scare when an infection had somehow got through to her and settled into her lungs, nearly killing her.

She was old — physically the oldest human in the System, probably. She felt as if she was underwater: her senses had turned to mush, so that she could barely feel, or taste, or see anything, as if she was encased in some deadening, viscous fluid. And her mind was failing.

She could feel it, toward the end. It was like a ghastly reverse run of her accelerated childhood; she woke every day to a new diminution of her self. She came to dread sleep, yet could not avoid it.

And every day, the bed seemed too large for her.

But she retained her pride; she couldn’t stand the indignity of it. She hated those who had put her into this position.

Her mother’s last visit to the habitat, a few days before the download, was bizarre. Lieserl, through her ruined, rheumy old eyes, was barely able to recognize Phillida — this young, weeping woman, only a few months older than when she had held up her baby girl to the Sun.

She could not forgive her mother for the artifice of her existence — for the way understanding of her nature, even data on Superet, had been kept from her until others thought she was ready.

Lieserl cursed Phillida, sent her away.

At last Lieserl was taken, in her bed, to the downloading chamber at the heart of Thoth. The chamber’s lid, disturbingly coffin-like, closed over her head. She closed her eyes; she felt her own, abandoned, frail body around her.

And then -

It was a sensory explosion. It was like sleeping, then waking — no, she thought; it was more — far more than that.

The focus of her awareness remained in the same functional hospital room at the center of the Solar habitat. She was standing, surveying the chamber — no, she realized slowly, she wasn’t standing: she had no real sensation of her body…

She felt disembodied, discorporeal. She felt an instant of panic.

But that moment of fear faded rapidly, as she looked out through her new eyes.

The drab, functional chamber seemed as vivid to her as the golden day she had spent as a small child, with her parents on that remote beach, when her senses had been so acute they were almost transparent. In an instant she had become young again, with every sense alive and sharp.

And, slowly, Lieserl became aware of new senses — senses beyond the human. She could see the sparkle of X-ray photons from the Solar photosphere as they leaked through the habitat’s shielding, the dull infra-red glow of the bellies and heads of the people working around the shell of her own abandoned body — and the fading sheen of that cold husk itself.

She probed inwards. She retained her memories from her old body, from prior to the downloading, she realized; but those memories were qualitatively different from the records she was accumulating now. Limited, partial, subjective, imperfectly recorded: like fading paintings, she thought.

She had died, and she was reborn. She felt pity, for the person who once called herself Lieserl.

The clarity of her new senses was remarkable. It was like being a child again. She immersed herself, joyously, in the objective reality of the Universe around her.

He — it — was a Virtual, of course. The realization brought Louise crushing disappointment.

Uvarov snorted. “This is an absurdity. A pantomime. You’re wasting my time here.”

The Virtual of Poole looked disconcerted; his smile faded. “How so?”

“I’ve read of Michael Poole. And I know he hated Virtuals, of all kinds.”

Virtual-Poole laughed. “All right. So this simulacrum is offensive; you think Poole would have objected. Well, perhaps. But at least it’s got your attention.”

Milpitas touched Uvarov’s arm. “Why are you so damn hostile, Doctor? No one’s doing you any harm.”

Uvarov snatched his arm away.

“She’s right.” Virtual-Poole waved a hand to the couches at the heart of the lifedome. “Why don’t you sit down? Do you want a drink, or — ”

“I don’t want to sit down,” Louise said icily. “And I don’t want a drink. What am I, a kid to be impressed by fireworks?” Even as she spoke, though, she was aware that the wormhole, sliding across space above them, had frozen in its track at the moment Virtual-Poole had climbed out of his couch; exotic-energy light flooded down over the little human tableau, as if suspending them in timelessness. She felt confused, disoriented. This isn’t Michael Poole. But all Virtuals were conscious, to some degree. This Virtual remembers being Poole. She wanted to lash out at it — to hurt it. “Damn it, it would have been cheaper to take us to Jupiter itself rather than to set up this charade, here on Earth.”

“Perhaps,” Virtual-Poole said drily. “But this diorama isn’t just for show. I have something to demonstrate to you. This setup seemed the best way to achieve that. As, if you’ve the patience, you’ll see.”

Louise felt her jaw muscles tighten. “Patience? I’m trying to launch a starship. I need to be at Port Sol, working on the Northern — not stuck here in this box in New York, talking to a damn puppet.”

Poole winced, looking genuinely hurt. Louise despised herself.

Uvarov said, “I, too, have projects which demand my time.”

The sky-blue light cast convincing shadows over Poole’s cheekbones and jaw. “This simulation is serving several purposes. And one of those purposes is discretion. Look — I’m only partially self-aware. But I am autonomous, within this environment. There is no channel in or out of here; no record will exist of this conversation, unless one of you chooses to make one.”

Milpitas snorted. “Why should we believe you? We still don’t know who you represent.”

A trace of anger showed in the hardening of Virtual-Poole’s mouth. “Now you’re being absurd. Why should I lie? Louise Ye Armonk, I have a proposal for you. A challenge — for you all, actually. You may refuse the challenge. You certainly can’t be forced to accept it. And so, we meet in secrecy; if you refuse, no one will ever know.”

“Bullshit,” Uvarov growled; pink Jovian light gleamed from his bald pate. “Let’s skip the riddles and get on with it. Who’s behind you, Poole?”

Briefly, Virtual-Poole looked pained — almost as if he was too tired for such confrontations. Louise remembered that although Michael Poole had accepted AS treatment, he’d persistently refused consciousness adjustment treatment. A deep dread of memory editing kept people like Poole away from the reloading tables, even when the efficiency of their awareness — clogged by decades of memory started to downgrade.

Virtual-Poole seemed to rouse himself. “Tell me what you know.”

Mark spoke up. “Very little. We got a call to come in here from the Port Sol authorities.” He smiled. “We got the impression we didn’t have a lot of choice but to comply. But it wasn’t clear who was behind the summons, or why we were wanted.”

Milpitas and Uvarov confirmed that they, too, had received similar calls.

“But,” Louise said drily, “it was obviously someone a bit more senior than the Port Sol harbor master.”

Virtual-Poole rubbed his nose; shadows moved convincingly across his hand. “Yes,” he said. “And no. You’ve no doubt heard of us. We don’t report to Port Sol — or to any single nation. We’re a private corporation, but we’re not working for profit. We get some backing from the UN, but also from most of the individual nation-states in the System as well. And a variety of corporations, who — ”

Louise studied Virtual-Poole suspiciously. “Who are you?”

Poole’s face stiffened, and Louise wondered how much restriction had been placed on the Virtual’s free will. Lethe, I hate sentience technology, she thought. Poole doesn’t deserve this.

Poole said, “I’m a representative of a group called Superet. The Holy Superet Light Church…”

“Superet.” Mark smiled. He looked relieved. “Is that all? Superet is innocuous enough. Isn’t it?”

“Maybe.” Virtual-Poole smiled. “Not everyone agrees. Superet is well known for the Earth-terraforming initiatives of the past. But not all Superet’s projects are simple balls of dry ice, you see. Some are rather more — ambitious. And not everyone thinks that projects with such timescales should be permitted to progress.”

Louise shoved her face forward, seeking understanding in the Virtual’s bland, simulated expression. “What timescales? How long-term?”

“Infinite,” Virtual-Poole said quietly. “Superet’s backers are people who wish to invest in the survival of the species itself, Louise.”

There was a long silence.

“Good grief.” Milpitas shook her head. “I don’t know about you, but I need to sit down. And how about that drink, Poole?”

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.

6

Like an insect circling an elephant the pod skimmed around the hull of the Great Northern.

Mark Wu, Louise Armonk, Garry Uvarov and Serena Milpitas sat and watched as their tiny pod skirted the starship. Their silence, Mark thought, was suitably deep and awe-struck, even for four who had been as close to the final stages of the project as these. And maybe that was Louise’s intention today, he thought, the subtext under what was ostensibly a simple inspection tour of the ship by her top management team.

Well, if so, she was certainly succeeding.

The lifedome of the Northern was a squat, transparent cylinder a mile wide. It was extraordinary to think that the whole of Michael Poole’s GUTship — drive section and all — would have fitted inside that sparkling box; Mark tried to imagine the Hermit Crab suspended in that great cylinder like some immense model under glass.

Mark could see clearly the multiple decks of the dome, and throughout the dome there was movement and light, and the deep, refreshing green of growing things. He was aware that the adaptation of much of the dome, and the rest of the ship, was still unfinished; most of what he saw was little more than a Virtual projection. But still he was impressed by the scale and vigor of it all. This lifedome would be a self-contained city — no, more than that: a world in itself, a biosphere suspended between the stars.

Home to five thousand people for a thousand years.

Now they wheeled to the underside of the lifedome. The pod approached the immense, tangled structure of the Northern’s main spine, and flew parallel to the spine for some three hundred yards toward the base of the dome.

The spine was a three-mile highway of metal littered with supply modules and antennae and other sensors, turned up to the distant stars like mouths. Behind them the spine led to the mysterious darkness of the drive section, where the lights of workers — human and robotic — crawled like flies. And, attached to the spine by bands of gold just before the drive section, was the huge Interface, the wormhole terminus which they would tow to the future. The tetrahedral frame looked like a gaudy, glittering toy of shining blue ribbon.

Uvarov spread his long, intelligent fingers and rested his hands against the gleaming hull of the pod. “Lethe,” he said. The pod’s lights struck highlights from his bony profile as he peered out at the spine. “It might not be real, but it’s beautiful.”

Louise laughed; beside the thin, gaunt eugenicist she looked short, compact, Mark thought. “Real enough,” she said. “The spine’s framework is a hundred percent realized. It’s just the superstructure that remains nebulous.” She thought for a moment, then called, “Configure 3-B.”

The flower-like antennae clustered along the spine melted away, dissolving into showers of pixel cubes which tumbled like snowflakes. For a few surreal seconds Virtual configurations of equipment modules blossomed over the spine; through the snowstorm of modules Mark could see the basic — and elegant structure of triangular vertebrae at the core of the spine.

At last the storm of images stilled; the spine settled into a new scattering of lenses and antennae. To Mark’s untutored eye this looked much the same as the original — perhaps rather sparser — but he became aware that Serena Milpitas was nodding, almost wistfully.

“This is the original configuration,” she said. “It’s what was planned when the ship was being designed for its oneway hop to Tau Ceti, just a century away.”

Mark studied Milpitas curiously. The project’s new chief engineer affected physical-forty, but Mark knew she was at least twice as old as that. He also knew there had been quite a bit of friction between Milpitas and Louise; so he was surprised to find, now, Milpitas praising Louise’s design. “You sound a little — nostalgic. Do you really think this is a better design?”

“Oh, yes.” Milpitas’ broad face split in a smile; she seemed surprised by the question. “Don’t you? Can’t you see it?”

Uvarov grunted. “Not particularly.”

“Inelegance was forced on us. Look — for a thousand-year flight the problems of reliability are enormous.” Her accent was broad, confident Martian. “This ship has around a thousand million distinguishable components. And all of them have to work perfectly, all of the time. Right? Now, we estimate that the chance of a significant failure of any one of those components — of a failure serious enough to knock out a ship’s system, say — is a tenth of one percent per year. Pretty good odds, you might think. But as the years go by the chances of a failure mount up, and they work cumulatively.” She fixed Mark with a direct stare. “What would you guess the chances of such a failure would be after a hundred years?”

Uvarov growled, “Oh, please, spare us games.”

Mark shrugged. “A few percent?”

“Not bad. Ten percent. Not wonderful, but liveable with.”

Uvarov clicked his tongue. “I hate your Mons Olympus grammar, engineer.”

Milpitas ignored him. “But after a thousand years, you’re looking at a failure probability of over sixty percent. You reach fifty-fifty after just seven centuries — ”

“What she’s trying to tell you,” Uvarov said heavily, his flat Lunar tones conveying his boredom, “is the obvious fact that they’ve had to perform extensive redesign to enable the ship to survive a thousand-year flight.”

“How? Louise doesn’t tell me a damn thing.”

Uvarov grinned. “Ex-wives never do. I should know. I — ”

Milpitas cut in, “With current technology, we couldn’t get the reliability rates high enough for the mechanical, electrical or semisentient components.” She waved a hand at the half-Virtual panorama beyond the hull. “Amazing, isn’t it? We think we’ve come so far. We thought that with nanobotic technology continual repair and replacement at the sub-visible level — reliability problems were a thing of the past. I mean, look at that spine out there. There’s sentience in it everywhere, right down to the nuts and bolts.”

“There are no nuts and bolts, Serena,” Louise said drily.

Milpitas ignored her. “And yet it doesn’t take much of a challenge to move us beyond the envelope of our capabilities. Strictly speaking, a thousand-year flight is still beyond our means.”

“That sounds ominous,” Mark said uneasily.

“So,” Louise said, “we had to look to the past — simple methods used to improve reliability on projects like the first off-Earth flights.” She called out, “Central configuration,” and the blizzard of virtual components swirled once more around the spine, settling at last into the pattern Mark remembered from before Louise’s change.

Milpitas pointed. “And this is what we’re going to the stars with. Look at it. Even at this gross macroscopic level you can see there are many more components.”

And, indeed, Mark realized now that there were more antennae, more sensor snouts, more maintenance pods; the spine structure looked busier, far more cluttered.

“Triple redundancy,” Milpitas said with a grimace. “Words — and a technique from the twenty-fifth century. Or further back, even, for all I know; probably from the time of those disgusting old fission reactors. Carrying three of everything — or more, for the key components — to reduce the chance of a catastrophe to the invisibly small.”

“Gripping,” Uvarov said. “But shall we move on, some time today? We do have the whole of the ship to inspect, as I recall.”

The base of the lifedome expanded in Mark’s vision until it covered the sky, becoming an immense, complex, semi-transparent roof; guide lights and the outlines of ports — large and small — encrusted the surface with color, and everywhere there was movement, a constant flow of cargo, pods and spacesuited figures through the multiple locks. Again Mark had the impression that this was not so much a ship as a city: immense, busy, occupied with the endless business of maintaining its own fabric.

Suspended beneath the lifedome, cradled in cables, was the dark, wildly incongruous form of the Great Britain. It looked like an immense lifeboat, suspended there, Mark thought; he grinned, relishing this evidence of Louise’s sentimentality.

The pod, working autonomously, made a flawless entry into one of the huge airlocks. After a couple of minutes the lock had completed its cycle.

The four of them emerged, drifting, into the air at the base of the Northern’s lifedome. It seemed to Mark that the base itself — constructed with the universal semisentient transparent plastic — was a wall dividing the Universe into two halves. Before him was the elaborate, sparkling-clean interior of the lifedome; behind him was the tough, angular spine of the GUTship, and the static darkness of transPlutonian space.

Louise led them to a row of zero-gee scooters; the scooters nuzzled against the transparent base, neat and efficient. Mark took a scooter. It was a simple platform, its pneumatic jets controlled by twists of its raised handles.

They formed into pairs — Louise and Uvarov in the lead, with Mark and Milpitas following. With near-silent sighs of scooter air the four moved off in formation, up toward the heart of the lifedome.

The lower fifth of a mile of the lifedome was known as the loading bay: a single, echoing hall, brilliantly lit and free of partitions. The roof of the loading bay — the underside of the first habitable section, called the maintenance bulkhead — was a mist-shrouded tangle of infrastructure, far above. Today, the loading bay was filled with bulky machinery and crates of supplies; huge masses, towed by people on scooters or by ’bots, crossed the air in all directions, emerging from a dozen locks.

Serena Milpitas performed a slow, easy spiral as she rose up through the air beside Mark. “I love these scooter things, don’t you?”

Mark smiled. “Sure. But they’re a lazy way to travel in zero gee. And they won’t be a lot of use when we’re underway.”

“No. A constant one-gee drive for a thousand years. What a drag.”

Mark studied the engineer as she went through her rolls; her expression was calm, almost vacuous, with every sign that she was lost in the simple physical pleasure of the scooter-ride. Mark said, “How did you feel about having to dig up those old techniques — the reliability procedures?”

“How did I feel?” Milpitas stabilized her scooter and studied Mark, a half-smile on her face. “You sound like a Keplerian… They’re dippier than anyone else back home on Mars. Ah, but I guess that’s your job, isn’t it? The social engineer.”

Mark smiled. “Maybe. But I’m off-duty now.”

“Sure you are.” Milpitas thought for a moment. “I guess our work isn’t so dissimilar, Mark. Your job — as I understand it — is to come up with ways for us to live with each other over a thousand years. Mine is to ensure that the ship itself — the external fabric of the mission — can sustain itself. When it came to redesigning Northern, I didn’t like messing up Louise’s nice, clean designs, frankly. But if you’re going to succeed at something like this you have to take no chances. You have to plan.” Her eyes lost their focus, as if she were looking at something far away. “It had to be done. And it was worth it. Anything’s worth it, for the project, of course.” Her expression cleared, and she looked at Mark, appearing confused. “Is that answering your question?”

“I think so.”

Mark hung back a little, and let Milpitas move ahead, up toward the complex maintenance bulkhead. He fell into line with Louise.

“You don’t look so happy,” Louise said.

Mark shrugged. “Just a little spooked by Serena, I guess.”

Louise snorted. “Aren’t we all.”

Many of the original crew of the Northern — who had, after all, seen themselves as potential colonists of the Tau Ceti system, not as time travelers with quasi mystical goals about saving the species — had decided not to stay with the ship after its new flight plan was announced by Louise. Louise had lost, for instance, the genial Sam Gillibrand, her original first assistant. On the other hand, Serena Milpitas — and Uvarov, for that matter — had seemed eager to join the project after its rescoping by Superet.

Both Milpitas and Uvarov seemed natural Superet supporters, to Mark; they’d absorbed with a chilling alacrity the induction programs Superet had offered them all.

Milpitas and Uvarov had become converts. Mark thought uneasily.

“You know, I always liked Sam Gillibrand,” he said wistfully. “Sam wants to go to Tau Ceti and build houses under the light of a new sun; the dark possibilities of five megayears hence couldn’t be of less interest to him. Serena is different, though. Under all that bluff Martian chatter and confident engineering, there’s something darker — more driven. Obsessive, even.”

“Maybe,” Louise said. “But, just as human engineering isn’t yet up to thousand year flights, so the average human head isn’t capable of thinking on thousand year timescales.” She sighed and ran her fingers through her close-cropped hair. “Serena Milpitas can win through for the mission, Mark. Both Milpitas and Uvarov seem able to think in millennia — megayears, even. And as a consequence, or as a cause, they are dark, multilevelled, complex people.” She looked at Mark sadly. “The Superet stuff is spooky, I agree. But I think it comes with the territory, Mark.”

Maybe in the complexities of the future the home-builders like Sam would be obsolete, their simple skills and motivation displaced in a dangerous Universe, Mark thought. Perhaps Superet and its converts represented the human of the future — the next wave of evolution, what the species would have to become to survive on cosmic timescales.

Maybe. But — judging by Milpitas and Uvarov — there wouldn’t be too many laughs.

Anyway, he thought gloomily, he was going to have ten centuries with these people to find out about them… And it was going to be Lethe’s own challenge for him to construct a viable society around them.

“It still surprises me that you agreed to sign up for this,” he said. “I mean, they took away your mission.”

Louise shrugged. “We’ve been over this enough times. Let’s face it, they would have taken Northern away from me anyway. I want to see the ship perform. And — ”

“Yes?”

She grinned. “Besides, after I got over my irritation at the way Superet runs its affairs, I realized no one’s ever tried a thousand-year flight before. Or tried to establish a time bridge across five million years. I can get one over on Michael Poole, wherever he is — ”

“Yes, but look what happened to him.”

Mark could see what was going on inside Louise’s head. With the Superet mission — with this immense stunt — she was going to be able to bypass the intimidating shadow of the future, simply by leaping over it. And she was obviously entranced by the idea of taking her technology to its limits. But he wondered if she really — really — had any idea of the scale of the problems they would face.

He opened his mouth to speak.

Louise, with unusual tenderness, laid a finder over his lips, closing them. “Come on, Mark. We’ve a thousand years to think of all the problems. Time enough. Today, the ship is bright and new; today, it’s enough for me to believe the mission is going to be fun.”

With a sudden access of vigor she twisted the handle of her scooter and hurried after the others.

Lieserl. Take it easy. You’re doing fine.

She looked up, tipping back her head. Already she was dropping out of the complex, exhilarating world of the convection region, with its immense turbulent cells, tangled flux tubes and booming p-waves. She stared upwards, allowing herself the luxury of nostalgia. The convective-zone cavern had come to seem almost homely, she realized.

Homely… at least compared to the regions she was going to enter now.

We’re still getting good telemetry, Lieserl.

“Good. I’m relieved.”

Lieserl, how are you feeling?

She laughed. With a mixture of exasperation and affection, she said, “I’ll feel better when you lose your ‘good telemetry’, Kevan, and I don’t have to listen to your dumb-ass questions any more.”

You’ll miss me when I’m gone.

“Actually,” Lieserl said, “that’s probably true. But I’m damned if I’m going to tell you so.”

Scholes laughed, his synthesized voice surprisingly unrealistic. You haven’t answered my question.

Her arms still outstretched, she looked down at her bare feet. “Actually, I feel a little like Christ. Dali’s Christ, perhaps, suspended in the air over an uncaring landscape.”

Yeah, Scholes said casually. My thought exactly.

Now she plunged through the last ghost-forms of convective cells. It was exactly like falling out of a cloud bank. The milky-white surface of the plasma sea was exposed beneath her; huge g-mode waves crawled across its surface, like thoughts traversing some huge mind.

Her rate of fall suddenly increased. It felt as if the bottom had dropped out of her stomach.

“Lethe,” she whispered.

Lieserl?

She found her chest tightening — and that was absurd, of course, because she had no chest. She struggled to speak. “I’m okay, Kevan. It’s just a little vertigo.”

Vertigo?

“Virtual vertigo. I feel like I’m falling. This illusion’s too damn good.”

Well, you are falling, Lieserl. Your speed’s increased, now you’re out of the convective stuff.

“I’m scared, Kevan.”

Take it easy. The telemetry is —

“Screw the telemetry. Just talk to me.”

He hesitated. You’re a hundred thousand miles beneath the photosphere. You’re close to the boundary of the radiative zone; the center of the Sun is another seven hundred thousand miles below you.

“Don’t look down,” she breathed.

Right. Don’t look down. Listen, you can be proud; that’s deeper than any probe we’ve dropped before.

Despite her fear, she couldn’t let that go. “So I’m a probe, now?”

Sorry. We’re looking at the new material squirting through the other end of your refrigerator-wormhole now. I can barely see the Interface for the science platforms clustered around it. It’s a great sight, Lieserl; we’ve universities from all over the System queuing up for observation time. The density of the gas around you is only about one percent of water’s. But it’s at a temperature of half a million degrees.

“Strong stuff.”

Angel tears, Lieserl…

The plasma sea was rushing up toward her, bland, devouring. Suddenly she was convinced that she, and her flimsy wormhole, were going to disappear into that well of fire with barely a spark. “Oh, Lethe!” She tucked her knees up to her chest and wrapped her arms around her lower legs, so that she was falling curled up in a fetal ball.

Lieserl, you’re not committed to this. If you want to pull out of there —

“No.” She closed her eyes and rested her forehead against her knees. “No, it’s all right. I’m sorry. I’m just not as tough as I think I am, sometimes.”

The wormhole is holding together. We think, after the redesign we’ve done, that you can penetrate at least the first few thousand miles of the radiative zone, without compromising the integrity of the wormhole. Maybe deeper; the temperature and pressure gradients are pretty small. But you know we didn’t advise this dive —

“I know it.” She opened her eyes and faced the looming sea once more. The fear was still huge, like a vice around her thinking. “Kevan, I’d never assemble the courage to go through this a second time. It’s now or never. I’ll even try to enjoy the ride.”

Stay with it, Lieserl.

“Yeah,” she growled. “And you stay with me — ”

Suddenly her fall was halted. It felt as if she had run into a wall of glass; her limbs spread-eagled against an invisible barrier and the breath was knocked out of her illusory lungs. Helpless, she was even thrown back up into the “air” a short distance; then her fall resumed, even more precipitately than before.

She screamed: “Kevan!”

We saw it, Lieserl. I’m still here; it’s okay. Everything’s nominal.

Nominal, she thought sourly. How comforting. “What in Lethe was that?”

You’re at the bottom of the convective layer. You should have been expecting something like that.

“Yes?” she snarled. “Well, maybe you should have damn well told me — yike!”

Again, that sudden, jarring arrest, followed by a disconcerting hurl into the air, as if she were an autumn leaf in the breeze.

Like snakes and bloody ladders, she thought.

You’re passing through the boundary layer between the radiative and connective zones, is all, Scholes said with studied calm. Below you is plasma; above you atomic gas — matter cool enough for electrons to stick to nuclei.

The photons emerging from the fusing core just bounce off the plasma, but they dump all their energy into the atomic gas. It’s the process that powers the connective zone, Lieserl. A process that drives connective founts bigger than worlds. So you shouldn’t be surprised if you encounter a little turbulence. In fact, out here we’re all interested by the fact that the boundary layer seems to be so thin…

We’re still tracking you, Lieserl; you shouldn’t be afraid. You’re through the turbulence now, aren’t you? You should be falling freely again.

“Yes. Yes, I am. So I’m in the sea, now?”

The sea?

“The plasma sea. The radiative zone.”

Yes.

“But — ”

Suddenly, almost without warning, the familiar skyscape of convection cells and flux tubes was misting from her sight, whiting out. There was whiteness above, before, below her; it was like being suspended inside some huge, chilling eggshell.

But what? What is it, Lieserl? What’s wrong?

For the first time she felt real panic creep around her mind.

“I can’t see, Kevan.”

Mark, rising through brightly lit air, looked down. He was nearing the top of the loading bay now. The base was a floor of glass far below him, with the spine and drive section ghostly forms beyond; people and ’bots criss-crossed the bay, hauling their cargo.

Mark tried to analyze his own impressions as they rose. For a moment he fought an irrational surge of vertigo: a feeling — despite the evidence of his eyes that he was in zero-gee — that if he tumbled from this scooter he would plummet to that floor of glass, far below. He concentrated on the environment close to him, the thick layer of warm, bright air all round him. But that made the glimpses of the spine and drive — the brutal limbs of the ship — seem unreal, as if the emptiness of space beyond the fragile walls of the dome was an illusion.

Mark felt uneasy. The ship was so huge, so complex — so convincing. After a few decades, it would be terribly easy to believe that this ship was a world, to forget that there was anything real, or significant, beyond its walls.

Now they were approaching the roof of the bay: the maintenance bulkhead. Mark drew level with Garry Uvarov, and they stared up at the mile-wide layer of engineering above them. The bulkhead was a tangle of pipes, ducts and cables, an inverted industrial landscape. There were even tree-roots, Mark saw. People and ’bots swarmed everywhere, working rapidly and apparently efficiently; even as Mark watched the bulkhead’s complex surface seemed to evolve, the ducts and tubes creeping across the surface like living things. It was a little like watching life spread through some forest of metal and plastic.

“Extraordinary how primitive it all is,” Mark said to Uvarov. “Cables and ducts — it’s like some sculpture from a museum of industrial archaeology.”

Uvarov waved a cultured hand toward the pipes above him. “We’re carrying human beings — barely-evolved, untidy sacks of water and wind — to the stars. We are cavemen inside a starship. That’s why the undersurface of this bulkhead seems so crude to you, Mark; it’s simply a reflection of the crudity of our own human design. We sail the stars. We even have nanobots to rebuild us when we grow old. But we remain primitives; and when we travel, we need immense boxes with pipes and ducts to carry our breath, piss and shit.” He grinned. “Mark, my passion my career — is the improvement of the basic human stock. Do you imagine the Xeelee carry all this garbage around with them?”

They passed through access ports in the maintenance bulkhead and ascended into the habitable sections.

There were fifteen habitable Decks in the mile-deep life-dome, each around a hundred yards apart. Some of the main levels were subdivided, so that the interior of the life-dome was a complex warren of chambers of all sizes. Elevator shafts and walkways pierced the Decks. The shafts were already in use as zero-gee access channels; they’d be left uncompleted, without machinery, until closer to departure.

Now the little party entered one shaft and began to rise, slowly, past the cut through Decks.

Many of the chambers were still unfinished, and a succession of Virtual designs were being tried out in some of them; Mark peered out at a storm of parks, libraries, domestic dwellings, theaters, workshops, blizzarding through the chambers.

Uvarov said, “How charming. How Earthlike. More concessions to the primitive in us, of course.”

Mark frowned. “Primitive or not, Uvarov, we have to take some account of human needs when designing an environment like this. As you should know. The chambers have been laid out on a human scale; it’s important people shouldn’t feel dwarfed to insignificance by the scale of the artifacts around them — or, on the other hand, cramped and confined by ship walls. Why, some of the chambers are so large it would be possible for an inhabitant to forget he or she was inside a ship at all.”

Uvarov grunted. “Really. But isn’t that more evidence that we as a species aren’t really yet up to a flight like this? It would be so easy to be immersed in the sensory impressions of the here-and-now, which are so much more real than the fragility of the ship, the emptiness outside the thin walls. It would be tempting to accept this ship as a world in itself, an invulnerable background against which we can play out our own tiny, complex human dramas, much as our distant forefathers did on the plains of Africa, billions of miles away.

“Think of the pipes and ducts under that maintenance bulkhead. Perhaps our ancestors, in simpler times, imagined that some such infrastructure lay underneath the flat Earth. The Universe was a box, with the Earth as its floor. The sky was a cow whose feet rested on the four corners of the Earth — or perhaps a woman, supporting herself on elbows and knees — or a vaulted metal lid. Around the walls of the box-world flowed a river on which the sun and moon gods sailed each day, entering and vanishing through stage doors. The fixed stars were lamps, suspended from the vault. And, presumably, underneath it all lay some labyrinth of tunnels and ducts through which the waters and the gods could travel to begin their daily journeys afresh. The heavens could change, but they were predictable; to the human consciousness — still half-asleep — this was a safe, contained, cozy, womb-like Universe. Mark Wu, is our Northern, today, so unlike the Earth as envisaged by — let us say — a Babylonian, or an Egyptian?”

Mark rubbed his chin. Uvarov’s patronizing style irritated him, but his remarks plugged in closely to his own vague sense of disquiet. “Maybe not,” he replied sharply. “But then you and I, and the others, have a responsibility to ensure that the inhabitants of the ship don’t slip back into some pre-rational state. That they don’t forget.”

“Ah, but will that be so easy, over a thousand years?”

Mark peered out at the half-built libraries and parks uneasily.

Uvarov said, “I’ve heard about some of the programs you and your social engineering teams are devising. Research initiatives and so forth — make-works, obviously.”

“Not at all.” Mark found himself bridling again. “I’m not going to deny we need to find something for people to do. As you keep saying, we’re primitives; we aren’t capable of sitting around in comfort for a thousand years as the journey unravels.

“Some of the work is obvious, like the maintenance and enhancement of the ship. But there will be programs of research. Remember, we’ll be cut off from the rest of the human Universe for most of the journey. Some of your own projects come into this category, Uvarov — like your AS enhancement program.” He thought about that, then said provocatively, “Perhaps you could come up with some way of replicating Milpitas’ triple-redundancy ideas within our own bodies.”

Uvarov laughed, unperturbed. “Perhaps. But I would hope to work in a rather more imaginative way than that, Mark Wu. After all AS treatment represents an enormous advance in our evolutionary history — one of our most significant steps away from the tyranny of the gene, which has ruthlessly cut us down since the dawn of our history. But must we rely on injections of nanobots to achieve this end? How much better it would be if we could change the fundamental basis of our existence as a species…”

Mark found Uvarov chilling. His cold, analytical view of humanity, coupled with the extraordinarily long-term perspective of his thinking, was deeply disturbing. The Superet conversion seemed only to have reinforced these trends in Uvarov’s personality.

And, Lethe, Uvarov was supposed to be a doctor.

“We should not be restrained by the primitive in us, Mark Wu,” Uvarov was saying. “We should think of the possible. And then determine what must be done to attain that… Whatever the cost.

“Your proposals for the social structure in this ship are another example of limited thinking, I fear.”

Mark frowned, his anger building. “You disapprove of my proposals?”

Uvarov’s voice, under its thick layer of Lunar accent, was mocking. “You have a draft constitution for a unified democratic structure — ”

“With deep splits of power, and local accountability. Yes. You have a problem with that? Uvarov, I’ve based my proposals on the most successful examples of closed societies we have — the early colonies on Mars, for example. We must learn from the past…”

Louise was the nominal leader of the expedition. But she wasn’t going to be a captain; no hierarchical command structure could last a thousand years. And there was no guarantee that AS treatments could sustain any individual over such a period. AS itself wasn’t that well established; the oldest living human was only around four centuries old. And who knew what cumulative effect consciousness editing would have, over centuries?

…So it could be that none of the crew alive at the launch — even Louise and Mark themselves — would survive to see the end of the trip.

But even if the last person who remembered Sol expired, Louise and her coterie had to find ways to ensure that the mission’s purpose was not lost with them.

Mark’s job was to design a society to populate the ship’s closed environment — a society stable enough to persist over ten centuries… and to maintain the ship’s core mission.

Uvarov looked skeptical. “But a simple democracy?”

Mark was surprised at the depth of his resentment at being patronized like this by Uvarov. “We have to start somewhere — with a framework the ship’s inhabitants are going to be able to use, to build on. The constitution will be malleable. It will even be possible, legally, to abandon the constitution altogether — ”

“You’re missing my point,” Uvarov said silkily. “Mark, democracy as a method of human interaction is already millennia old. And we know how easy it is to subvert any democratic process. There are endless examples of people using a democratic system as a games-theory framework of rules to achieve their own ends.

“Use your imagination. Is there truly nothing better? Have we learned nothing about ourselves in all that time?”

“Democracies don’t go to war with each other, Uvarov,” Mark said coldly. “Democracies — however imperfectly — reflect the will of the many, not the few. Or the one.

“As you’ve told me, Uvarov, we remain primitives. Maybe we’re still too primitive to trust ourselves not to operate without a democratic framework.”

Uvarov bowed his elegant, silvered head — but without conviction or agreement, as if merely conceding a debating point.

The four scooters rose smoothly past the half-finished Decks.

7

She was suspended in a bath of charged particles. It was isotropic, opaque, featureless…

She had entered a new realm of matter.

Lieserl. Lieserl! I know you can hear me; I’m monitoring the feedback loops, just listen to me. Your senses are overloaded; they are going to take time to adapt to this environment. That’s why you’re whited out. You’re not designed for this, damn it. But your processors will soon be able to interpret the neutrino flux, the temperature and density gradients, even some of the g-mode patterns, and construct a sensorium for you. You’ll be able to see again, Lieserl; just wait for the processors to cut in…

The voice continued, buzzing in her ear like some insect. It seemed irrelevant, remote. In this mush of plasma, she couldn’t even see her own body. She was suspended in isotropy and homogeneity — the same everywhere, and in every direction. It was as if this plasma sea, this radiative zone, were some immense sensory-deprivation bath arranged for her benefit.

But she wasn’t afraid. Her fear was gone now, washed away in the pearl-like light. The silence…

Damn it, Lieserl, I’m not going to lose you now! Listen to my voice. You’ve gone in there to find dark matter, not to lose your soul.

Lieserl, lost in whiteness, allowed the still, small voice to whisper into her head.

She dreamed of photinos.

Dark matter was the best candidate for aging the Sun.

Dark matter comprised all but one hundredth of the mass of the Universe; the visible matter — baryonic matter which made up stars, galaxies, people — was a frosting, a thin scattering across a dark sea.

The effects of dark matter had been obvious long before a single particle of the stuff had been detected by human physicists. The Milky Way galaxy itself was embedded in a flattened disc of dark matter, a hundred times the mass of its visible components. The stars of the Milky Way didn’t orbit its core, as they would in the absence of the dark matter; instead the galaxy turned as if it were a solid disc — the illuminated disc was like an immense toy, embedded in dark glass.

According to the Standard Model there was a knot of cold, dark matter at the heart of the Sun — perhaps at the heart of every star.

And so, Lieserl dreamed, perhaps it was dark matter, passing through fusing hydrogen like a dream of winter, which was causing the Sun to die.

Now, slowly, the isotropy bleached out of the world. There was a hint of color a pinkness, a greater warmth, its source lost in the clouds below her. At first she thought this must be some artifact of her own consciousness — an illusion concocted by her starved senses. The shading was smooth, without feature save for its gradual deepening, from the zenith of her sky to its deepest red at the nadir beneath her feet. But it remained in place around her, objectively real, even as she moved her head. It was out there, and it was sufficient to restore structure to the world — to give her a definite up and down.

She found herself sighing. She almost regretted the return of the external world; she could very quickly have grown accustomed to floating in nothingness.

Lieserl. Can you see that? What do you see?

“I see elephants playing basketball.”

Lieserl —

“I’m seeing the temperature gradient, aren’t I?”

Yes. It’s nice to have you back, girl.

The soft, cozy glow was the light of the fusion hell of the core, filtered through her babyish Virtual senses.

There was light here, she knew — or at least, there were photons: packets of X-ray energy working their way out from the core of the Sun, where they were created in billions of fusion flashes. If Lieserl could have followed the path of a single photon, she would see it move in a random, zigzag way, bouncing off charged particles as if in some subatomic game. The steps in the random walk traversed at the speed of light — were, on average, less than an inch long.

The temperature gradient in this part of the Sun was tiny. But it was real, and it was just sufficient to encourage a few of the zigzagging photons to work their way outwards to the surface, rather than inwards. But the paths were long — the average photon needed a thousand billion billion steps to reach the outer boundary of the radiative layer. The journey took ten million years — and because the photons moved at the speed of light, the paths themselves were ten million light-years long, wrapped over on themselves like immense lengths of crumpled ribbon.

Now, as other “senses” cut in, she started to make out more of the environment around her. Pressure and density gradients showed up in shades of blue and green, deepening in intensity toward the center, closely matching the temperature differentials. It was as if she were suspended inside some huge, three-dimensional diagram of the Sun’s equation of state.

As if on cue, the predictions of the Standard Model of theoretical physics cut in, overlaying the pressure, temperature and density gradients like a mesh around her face. The divergences from the Standard Model were highlighted in glowing strands of wire.

There were still divergences from the Model, she saw. There were divergences everywhere. And they were even wider than before.

Dark matter and baryonic matter attracted each other gravitationally. Dark matter particles could interact with baryonic matter through other forces: but only feebly, and in conditions of the highest density — such as at the heart of stars. In Earthlike conditions, the worlds of baryonic and dark matter slid through and past each other, all but unaware, like colonies of ghosts from different millennia.

This made dark matter hard to study. But after centuries of research, humans had succeeded in trapping a few of the elusive particles.

Dark matter was made up of sparticles — ghostly mirror-images of the everyday particles of baryonic matter.

Images in what mirror? Lieserl wondered feebly. As she framed the question the answer assembled itself for her, but — drifting as she was — it was hard to tell if it came from the voice of Kevan Scholes, or from the forced-learning she’d endured as a child, or from the data stores contained within her wormhole.

Hard to tell, and harder to care.

The particle mirror was supersymmetry, the grand theory which had at last shown how the diverse forces of physics — gravitational, electromagnetic, strong and weak nuclear — were all aspects of a single, unified superforce. The superforce emerged at extremes of temperature and pressure, shimmering like a blade of some tempered metal in the hearts of supernovas, or during the first instants of the Big Bang itself. Away from these extremes of time and space, the superforce collapsed into its components, and the supersymmetry was broken.

Supersymmetry predicted that every baryonic particle should have a supersymmetric twin: a sparticle. The electron was paired with a selectron, the photon with the photino — and so on.

The particular unified-theory variant called Spin (10) had, with time, become the standard. Lieserl rolled that around her tongue, a few times. Spin (10). A suitably absurd name for the secret of the Universe.

The divergence, of theory from observation, was immense — and increased toward the center of the Sun.

“Kevan, it’s way too hot out here.”

We see it, Lieserl, he said wryly. For now we’re just logging the data. Just as well you didn’t pack your winter coat.

She looked within herself, at some of her subsidiary senses. “And I’m already picking up some stray photino flux.”

Already? This far out from the center? Scholes sounded disturbed. Are you sure?

As a star like the Sun swept along its path about the center of the galaxy through a huge, intangible sea of dark matter — photinos fell into its pinprick gravity well, and clustered around its heart.

The photinos actually orbited the center of the Sun, swarming through its core around the geometric center like tiny, circling carrion-eaters, subatomic planets with orbital “years” lasting mere minutes. The photinos passed through fusing hydrogen as if it were a light mist…

Almost.

The chances of a photino interacting with particles of the plasma were remote but not zero. Once every orbit, a photino would scatter off a baryonic particle, perhaps a proton. The photino took some energy away from the proton. The gain in energy boosted the orbital speed of the photino, making it circle a little further out from the heart of the Sun.

Working this way, passing through the fusing hydrogen with its coagulated mass of trapped photons, the photinos were extremely efficient at transporting heat out from the center of the Sun.

According to the Standard Model, the temperature at the center should have been suppressed by a tenth, and the fusion heat energy smoothed out into the surrounding, cooler regions, making the central regions nearly isothermal — at a uniform temperature. The core would be a little cooler than it should otherwise have been, and the surrounding material a little warmer.

…Just a little. According to the Standard Model.

Now, Lieserl studied the temperature contours around her and realized how far the reality diverged from the ancient, venerated theoretical image. The isothermal region stretched well beyond the fusion core — far, far beyond the predictions of the Standard Model with its modest little knot of circling photinos.

“Kevan, there is much more heat being sucked out of the core than the Standard Model predicted. You do realize that there’s no way the Model can be made to fit these observations.”

No. There was a silence, and Lieserl imagined Scholes sighing into his microphone. I guess this means goodbye to an old friend.

She allowed the contour forms of the Standard Model to lapse from her sensorium, leaving exposed the gradient curves of the physical properties of the medium around her. Without the spurious detail provided by the overlay of Standard Model contours, the gradient curves seemed too smooth, deceptively featureless; she felt a remnant of her earlier deprived-sensorium tranquility return to her. There was no sense of motion, and no real sense of scale; it was like being inside overlaid clouds glowing pink and blue from some hidden neon source.

“Kevan. Am I still falling?”

You’ve reached your nominal depth now.

“Nominal. I hate that word.”

Sorry. You’re still falling, but a lot more slowly; we want to be sure we can handle the energy gradients.

But she’d barely breached the surface of the plasma sea; eighty percent of the Sun’s radius — a full two light-seconds — still lay beneath her.

And you’re picking up some lateral drift, also. There are currents of some kind in there, Lieserl.

It was as if her Virtual senses were dark-adapting; now she could see more structure in the waxy temperature-map around her: pockets of higher temperature, slow, drifting currents. “Right. I think I see it. Convection cells?”

Maybe. Or some new phenomenon. Lieserl, you’re picking up data they’ve never seen before, out here. This stuff is only minutes old; it’s a little early to form hypotheses yet, even for the bright guys in Thoth.

I wish you could see the Interface — out here, at the other end of your heat sink. Deep Solar plasma is just spewing out of it, pumping from every face; it’s as if a small nova has gone off, right at the heart of the System. Lieserl, you may not believe this, but you’re actually illuminating the photosphere. Why, I’ll bet if we looked hard enough we’d find you were casting shadows from prominences.

She smiled.

I can hear you smiling, Lieserl. I’m smart like that. You enjoy being the hero, don’t you?

“Maybe just a little.” She let her smile broaden. I’m casting shadows onto the Sun. Not a bad monument.

The uppermost level of the Northern’s habitable section was a square mile of rain forest.

The four air-scooters rose through a cylindrical Lock. Mark found himself rising up, like some ancient god, into the midst of jungle.

The air was thick, stifling, laden with rich scents and the cries and hoots of birds and animals. He was surrounded by the branchless boles of trees, pillars of hardwood — some extravagantly buttressed — that reached up to a thick canopy of leaves; the boles disappeared into the gloom, rank on rank of them, as if he were inside some nature-born temple of Islam. The floor of the forest, starved of light by the canopy, was surprisingly bare and looked firm underfoot: it was a carpet of leaves, pierced by Lock entrances which offered incongruous glimpses of the cool, huge spaces beneath this sub-world. Fungi proliferated across the floor, spreading filaments through the leaf litter and erecting fruiting bodies in the shape of umbrellas and globes, platforms and spikes hung about by lace skirts.

On a whim, Mark rose through a hundred feet alongside the rotting carcass of a dead tree. The bark was thick with ferns and mosses which had formed a rich compost in the bark’s crevices. Huge, gaudy orchids and bromeliads had colonized the bark, drawing their sustenance from leaf mold and collecting moisture from the air with their dangling roots.

He drew alongside a wild banana. Its broad, drooping leaf was marked by a line of holes on either side of the midrib. Mark lifted the leaf, and found suspended from the underside a series of white, fur-coated balls perhaps two inches across: nomadic bats, sheltering from the rainfall of this artificial forest.

There was a motion behind him; he turned.

Uvarov had followed him, and was now watching appraisingly. “Each day,” Uvarov intoned, his face long in the gloom, “an artificial sun will ride its chariot across the glass sky of this jungle-world. And machines will pipe rainfall into artificial clouds. We’re living in a high-technology realization of our most ancient visions of the Universe. What does the fact that we’ve built this ship in such a way tell us about ourselves, I wonder?”

Mark didn’t answer. He pushed himself away from the tree, and they descended to join the others, just above the forest floor.

Louise slapped the bole of a tree. She grinned. “One of the few real objects in the whole damn ship,” she said. She looked around. “This is Deck Zero. I wanted our tour today to end here. I’m proud of this forest. It’s practical — it’s going to be the lungs of the ship, a key part of our ecology — and it has higher purposes too; with this aboard we’ll never be able to forget who we are, and where we came from.”

She looked from one to the other, in the green gloom. “We’ve all come into this project from different directions. I’m interested in the technical challenge. And some of you, with Superet sympathies, have rather more ambitious goals to achieve. But we four, above all others, have the responsibility of making this project work. The forest is a symbol for us all. If these trees survive our ten centuries, then surely our human cargo will too.”

Serena Milpitas tilted back her head; Mark followed her example, and found himself peering up at the remote stars through a gap in the canopy. Suddenly he had a shift of perspective — a discontinuity of the imagination which abruptly revealed to him the true nature of this toy jungle, with empty, lightless space above it and a complex warren of humans below.

Garry Uvarov said, “But if the Superet projections are correct, who knows what stars will be shining down on these trees in a thousand years?”

Mark reached out and touched a tree bole; he found something comforting about its warm, moist solidity. He heard a shrieking chorus, high above him; in the branches above his head he saw a troupe of birds of paradise — at least a dozen of them — dancing together, their ecstatic golden plumage shimmering against the transPlutonian darkness beyond the skydome.

A thousand years…

Dark matter could age a star.

The photino knot at the heart of the Sun lowered the temperature, and thereby suppressed the rate of fusion reaction. Naively, Lieserl supposed, one might think that this would extend the life of the Sun, not diminish it, by slowing the rate at which hydrogen was exhausted.

But it didn’t work out like that. Taking heat energy out from the core made the Sun more unstable. The delicate balance between gravitational collapse and radiative explosion was upset. The Sun would reach turnoff earlier — that is, it would leave the Main Sequence, the family of stable stars, sooner than otherwise.

According to the Standard Model, photinos should reduce the life of the Sun only by a billion years.

Only?

A billion years was a long time — the Universe itself was only around twenty billion years out of its Big Bang egg — but the Sun would still be left with many billions of years of stable, Main Sequence existence…

According to the Standard Model. But she already knew the Model was wrong, didn’t she?

Lieserl.

“Hmm?”

We have the answer. We think.

“Tell me.”

The Standard Model predicts the photino cloud should be contained within the fusing core, within ten percent of the total Solar diameter. Right? But, according to the best fits we’ve made to your data —

“Go on, Kevan.”

There are actually significant photino densities out to thirty percent of the diameter. Three times as much as the Model; nearly a third of the —

“Lethe.” She looked down. The heart of the Sun still glowed peacefully in interleaved shades of pink and blue. “That must mean the fusion core is swamped with photinos.”

Even through the crude wormhole telemetry link she could hear the distress in his voice. The temperature at the center is way, way down, Lieserl. In fact —

“In fact,” she said quietly, “it’s possible the fusion processes have already been extinguished altogether. Isn’t it, Kevan? Perhaps the core of the Sun has already gone out, like a smothered flame.”

Yes. Lieserl, the most disturbing thing for me is that no one here can come up with a mechanism for such a photino cloud to form naturally…

“What’s the lifecycle prediction? How long has the Sun left to live?”

No hesitation this time. Zero.

At first the blunt word made no sense. “What?”

Zero, on the scales we’re talking about — timescales measured in billions of years. In practice, we’re looking at perhaps one to ten million years left. Lieserl, that’s nothing in cosmic terms.

“I know. But it ties in with the predictions out of Superet, doesn’t it? The data they collected through Michael Poole’s wormhole daisy-chain.”

Yes.

“Kevan, you shouldn’t feel too distressed. Five million years is fifty times the length of human history so far — ”

Maybe. Kevan’s voice took on a harder edge, as if he personally resented the aging of the Sun. But I have kids. I hope to have descendants still alive in five million years. Damn it, I hope to be sentient still myself. Why not? It’s only five megayears; we’re out of the Dark Ages now, Lieserl.

She peered deep into the heart of the Sun, subvocally trying to press more of her functions into play. She had senses to pick up the ghostly shades of neutrino and photino fluxes, and if she just — tried — hard enough, she ought to be able to make out the dark matter cloud itself.

“I’ll have to go deeper,” she murmured.

What?

“I said I’m going deeper. I want to find out what’s down there. In the core.”

Lieserl —

“Come on, Kevan. Spare me any warnings about caution. You can’t tell me that Superet has invested so much in me so far, only to have me turn back just inside the damn photosphere.”

You’ve already achieved an astonishing amount.

“And I can achieve a lot more. I’m going in, Kevan. Just as I’ve been designed to. I want to see just what has put out our Sun.” Or, she thought uneasily, who.

Scholes hesitated. The truth is, you’re only an experiment, Lieserl. Damn it, we didn’t even know what conditions you would encounter in there.

“So I’ll take my time. You can redesign me en route. I’ve all the time in the world.

“I’ll follow the bouncing photons. Maybe it will take me a million years to drift into the center. But I’m going to get there.”

Lieserl, Superet wants you to go on. But — you must listen to this — it is prepared to risk you not returning. Your trip could be one way, Lieserl. Do you understand? Lieserl?

She shut out the whispering, remote voice, and stared into the oceanic depths of the Sun.