SILVER GHOST

AD 5499

Minda didn't even see the volcanic plume before it swallowed up her flitter.

Suddenly the fragile little craft was turning end over end, alarms wailing and flashing, all its sensors disabled. But to Minda, feeling nothing thanks to her cabin's inertial suspension, it was just a light show, a Virtual game, nothing to do with her.

Just seconds after entering the ash plume, the flitter rammed itself upside down into an unfeasibly hard ground. Crumpling metal screamed. Then the inertial suspension failed. Minda tumbled out of her seat, and her head slammed into the cabin roof.

Immersed in sudden silence, sprawled on the inverted ceiling, she found herself staring out of a window. Gushing vapour obscured the landscape. That was air, she thought woozily. The frozen air of this world, of Snowball, blasted to vapour by the flitter's residual heat.

All she could think of was what her cadre leader would have to say. You fouled up, Bryn would tell her. You don't deserve to survive. And the species will be stronger for your deletion.

I'm fifteen years old. I'm strong. I'm not dead yet. I'll show her.

She passed out.

Maybe she awoke, briefly. She thought she heard a voice.

`. . . You are a homeotherm. That is, your body tries to maintain a constant temperature. It is a common heat management strategy. You have an inner hot core, which appears to comprise your digestive organs and your nervous system, and an outer cooler shell, of skin and fat and muscle and limbs. The outer shell serves as a buffer between the outside world and the core. Understanding this basic mechanism should help you survive . . .'

Through the window, between gusts of billowing mist, she glimpsed something moving: a smooth curve sliding easily past the wreck, a distorted image of a crumpled metallic mass. It couldn't be real, of course. Nothing moved on this cold world.

When she woke up properly, it was going to hurt. She closed her eyes.

When she couldn't stay unconscious any longer, she was relieved to find she could move.

She climbed gingerly out of the crumpled ceiling panel. She probed at her limbs and back. She seemed to have suffered nothing worse than bruises, stiffness and pulled muscles.

But she was already feeling cold. And she had a deepening headache that seemed to go beyond the clatter she had suffered during the landing.

Her cabin had been reduced to a ball, barely large enough for her to stand up. The only light was a dim red emergency glow. She quickly determined she had no comms, not so much as a radio beacon to reveal her position - and there was only a trickle of power. Most of the craft's systems seemed to be down - everything important, anyhow. There was no heat, no air renewal; maybe she was lucky the gathering cold had woken her before the growing foulness of the air put her to sleep permanently.

But she was stuck here. She sat on the floor, tucking her knees to her chest.

It all seemed a very heavy punishment for what was, after all, a pretty minor breach of discipline.

OK, Minda shouldn't have taken a flitter for a sightseeing jaunt around the glimmering curve of the new world. OK, she shouldn't have gone solo, and should have lodged and stuck to a flight plan. OK, she shouldn't have flown so low over the ruined city.

But the fact was that after grousing her way through the three long years of the migration flight from Earth - three years, a fifth of her whole life - she'd fallen in love with this strange, lonely, frozen planet as soon as it had come swimming toward her through sunless space. She had sat glued before Virtual representations of her new home, tracing ocean beds with their frozen lids of ice, continents coated by sparkling frost - and the faint, all-but-erased hints of cities and roads, the mark of the vanished former inhabitants of this unlucky place. The rest of her cadre were more interested in Virtual visions of the future, when new artificial suns would be thrown into orbit around this desolate pebble. But it was Snowball itself that entranced Minda - Snowball as it was, here and now, a world deep-frozen for a million years.

As the Spline fleet had lumbered into orbit - as she had endured the ceremonies marking the claiming of this planet on behalf of the human species and the Coalition - she had itched to walk on shining lands embedded in a stillness she had never known in Earth's crowded Conurbations.

Which was why, just a week after the first human landing on Snowball, she had gotten herself into such a mess.

Well, she couldn't stay here. Reluctantly she got to her feet.

With a yank on a pull-tag, her seat cushion opened up into a survival suit. It was thick and quilted, with an independent air supply and a sewn-in grid of heating elements and lightweight power cells. She sealed herself in. Clean air washed over her face, and the suit's limited medical facilities probed at her torn muscles.

She had to trigger explosive bolts to get the hatch open. The last of the flitter's air gushed out into a landscape of silver and black, and crystals of frost fell in neat parabolas to an icebound ground. Though she was cocooned in her suit, she felt a deeper chill descend on her.

And as the vapour froze out, again she glimpsed strange sudden movement - a surface like a bubble, or a distorting mirror - an image of herself, a silvery figure standing framed in a doorway, ruddy light silhouetting her. The image shrank away.

It had been like seeing a ghost. This world of death might be full of ghosts. I should be scared, she thought. But I'm walking away from a volcanic eruption and a flitter crash. One thing at a time, Minda. Clumsily she clambered through the crash-distorted hatchway.

She found herself standing in a drift of loose, feathery snow that came up to her knees. Beneath the snow was a harder surface: perhaps water ice, even bare rock. Where her suit touched the snow, vapour billowed around her.

To her left that volcano loomed above the horizon, belching foul black fast-moving plumes that obscured the stars. And to her right, in a shallow valley, she made out structures - low, broken walls, perhaps a gridwork of streets. Everything was crystal clear: no mist to spoil the view on this world, where every molecule of atmosphere lay as frost on the ground. The sky was black and without a sun - yet it was far more crowded than the sky of Earth, for here, at the edge of the great interstellar void known as the Local Bubble, the hot young stars of Scorpio were close and dazzling.

The landscape was wonderful, what she had borrowed the flitter to come see. And yet it was lethal: every wisp of gas around her feet was a monument to more lost heat. Her fingers and toes were already numb, painful when she flexed them.

She walked around the crash site. The flitter had dug itself a trench. And as it crashed the flitter had let itself implode, giving up its structural integrity to protect the life bubble at its heart - to protect her. The craft had finished up as a rough, crumpled sphere. Now it had nothing left to give her.

Her suit would expire after no more than a few hours. She had no way to tell Bryn where she was - they probably hadn't even missed her yet. And she and her flitter made no more than a metallic pinprick in the hide of a world as large as Earth.

She was, she thought wonderingly, going to die here. She spoke it out loud, trying to make it real. `I'm going to die.' But she was Minda. How could she die? Would history go on after her? Would mankind sweep on, outward from the Earth, an irresistible colonising wave that would crest far beyond this lonely outpost, with her name no more than a minor footnote, the first human to die on the new world? `I haven't done anything yet. I haven't even had sex properly-'

A vast, silvered epidermis ballooned before her, and a voice spoke neutrally in her ear.

`Nor, as it happens, have I.'

It was the silver ghost.

She screamed and fell back in the snow.

001

A bauble, silvered, perhaps two metres across, hovered a metre above the ground, like a huge droplet of mercury. It was so perfectly reflective that it was as if she couldn't see it at all: only a fish-eye reflection of the flitter wreck and her own sprawled self, as if a piece of the world had been cut out and folded over.

And this silvery, ghostly, not-really-there creature was talking to her.

`Native life forms are emerging from dormancy,' said a flat, machine-generated voice in her earpieces. `Your heat is feeding them. To them you are a brief, unlikely summer. How fascinating.'

Clumsy in her thick protective suit, bombarded by shocks and strangeness, she twisted her head to see.

The snow was melting all around her, gushing up in thin clouds of vapour that quickly refroze and fell back, so that she was lying in the centre of a spreading crater dug out of the soft snow. And in that crater there was movement. Colours spread over the ice, all around her: green and purple and even red, patches of it like lichen, widening as she watched. A clutch of what looked like worms wriggled in fractured ice. She even saw a tiny flower push out of a mound of frozen air, widening a crimson mouth.

Struck with revulsion, she stumbled to her feet. With her heat gone the life forms dwindled back. The colours leached out of the lichen-like patches, and that single flower closed, as if regretfully.

`A strange scene,' said the silver ghost. `But it is a common tactic. The living things here must endure centuries in stillness and silence, waiting a chance benison of heat - from volcanic activity, perhaps even a cometary impact. And in those rare, precious moments, they live and die, propagate and breed. Perhaps they even dream of better times in the past.'

Though she had endured orientation exercises run by the Commission for Historical Truth, Minda had never encountered an alien before. She bunched her fists. `Are you a Qax?'

`. . . No,' it replied, after some hesitation. `Not a Qax.'

`Then what?'

Again that hesitation. `Our kinds have never met before. You have no name for me. What are you?'

`I'm a human being,' she said defiantly. She pushed out her chest; her suit was emblazoned with a green tetrahedron. `And this is our planet. You'll see, when we get it sorted out. These things, these flowers and worms, cannot compete with us.'

The ghost hovered, impassive. `Compete?'

She swivelled her head to confront the hovering ghost. `All life forms compete. It is the way of things.' But it was as if her skull was full of a sloshing liquid; she felt herself stumbling forward.

`Try to stay upright,' the ghost said, its voice free of inflection. `Your insulation is imperfect. To reduce heat loss, you must minimise your surface contact with the ice.'

`I don't need your advice,' she growled. But her breath was misting, and there were tiny frost patterns in the corners of her faceplate. The cold was sharp in her nose and mouth and eyes.

The ghost said, `Your body is a bag of liquid water. I surmise you come from a world of high ambient temperatures. I, however, come from a world of cold.'

`Where?'

The hovering globe's hide was featureless, but nevertheless she had the impression that it was spinning. `Towards the centre of the Galaxy.' Something untranslatable. A distance? `And yours?'

She knew how to find the sun from here. Minda had travelled across a hundred and fifty light years, at the edge of the great colonising bubble called the Third Expansion, towards the brilliant young stars of Scorpio and the Southern Cross. Now those dazzling beacons were easily identifiable in the sky over her head, jewels thrown against the paler wash of the Galaxy centre. To find home, all she had to do was look the other way, back the way the great fleet of Spline ships had come. The sun, Earth and all the familiar planets were therefore somewhere beneath her feet, hidden by the bulk of this frozen rock.

She was never going to see Earth again, she thought suddenly, desolately; and because this ice-block world happened to be turned this way rather than that, she would never even see the dim, unremarkable patch of sky where Earth lay.

Without thinking, she found herself looking that way. She snapped her head up. `I mustn't tell you.'

`Ah. Competition?'

Was the ghost somehow mocking her? She said sharply, `If we have never met before, how come I understand you?'

`Your vessel carries a translator box. The box understands both our languages. It is of Squeem design.'

Minda hadn't even known her flitter was equipped with a translator box. `It's a human design,' she said.

`No,' the ghost said gently. `Squeem. We have never met before, but evidently the Squeem have met us both. Ironic. It is a strange example of inadvertent cooperation between three species: Squeem, your kind, mine.'

The Squeem were the first extra-solar species humanity had encountered. They were also the first to have occupied Sol system; the Qax, soon after, had been the second. Minda had grown up understanding that the universe was full of alien species hostile to humanity. She glanced around. Were there more silver ghosts out there, criss-crossing the silent plains, their perfect reflectiveness making them invisible to her untrained eye? She tried not to betray her fear.

She asked cautiously, `Are you alone?'

`We have a large colony here.' Again that odd hesitation. `But I, too, am stranded in this place. I came to investigate the city.'

`And you were caught by the volcano?'

`Yes. What is worse, my investigation did not advance the goals of the colony.' She sensed it was studying her. `You are shivering. Do you understand why? Your body knows it is losing heat faster than it is being replaced. The shivering reflex exercises many muscles, increasing heat production by burning fuel. It is a short-term tactic, but-'

`You know a lot about human bodies.'

`No,' it said. `I know a lot about heat. I am equipped to survive in this heat-sink landscape for extended periods. You, however, are not.'

It was as if cadre-leader Bryn was lecturing her on the endless struggle that was the only future for mankind. We cannot be weak. The Qax found us weak. They enslaved us and almost wiped our minds clean. If we are unfit for this new world, we must make ourselves fit. Whatever it takes. For only the fittest survive. If she let herself die before this enigmatic silver ghost, she would be conceding the new world to an alien race.

Impulsively, she began to stalk into the shallow valley, towards the antique city. Maybe there was something there she could use to signal, or survive.

The silver ghost followed her. It swam over the ground with a smooth, unnatural ease; it was a motion neither biological nor mechanical that she found disturbing.

She pushed through snowed-out air. The cold seemed to be settling in her lungs, and when she spoke her voice quavered from shivering.

`Why are you here? What do you want on Snowball?'

`We are' - a hesitant pause - `researchers. This world is like a laboratory to us. This is a rare place, you see, because near-collisions between stars, of the kind that hurled this world into the dark, are rare. We are conducting experiments in low-temperature physics.'

`You're talking about absolute zero. Everybody knows you can't reach absolute zero.'

`Perhaps not. But the journey is interesting. The universe was hot when it was born,' the ghost said gently. `Very hot. Since then it has expanded and cooled, slowly. But it still retains a little of that primal warmth. In the future, it will grow much colder yet. We want to know what will happen then. For example, it seems that at very low temperatures quantum wave functions - which determine the position of atoms - spread out to many times their normal size. Matter condenses into a new jelly-like form, in which all the atoms are in an identical quantum state, as if lased . . .'

Minda didn't want to admit she understood none of this.

The ghost said, `You see, we seek to study matter and energy in configurations which might, perhaps, never before have occurred in all the universe's history.'

She clambered over low, shattered walls, favouring hands and feet which ached with the cold. `That's a strange thought.'

`Yes. How does matter know what to do, if it has never done it before? By probing such questions we explore the boundaries of reality.'

She stopped, breathing hard, and gazed up at the hovering ghost. `Is that all you do, this physics stuff? Do you have a family?'

`That is . . . complicated. More yes than no. Do you?'

`We have cadres. I met my parents before I left home. They were there at my Naming, too, but I don't remember that. Do you have music?'

`More yes than no. We have other arts. Tell me why you are here.'

She frowned. `We have a right to be here.' She waved an arm over the sky. `Some day humans are going to reach every star in the sky, and live there.'

`Why?'

`Because if we don't, somebody else will.'

`Is that all you do?' the ghost asked. `Fly to the stars and build cities and compete?'

`No. We have music and poetry and other stuff.' Defensively, she plodded on through deepening snow. `Soon we'll change this world. We're going to terraform it.' She had to explain what that meant. `It will be a heroic project. It will require hard work, ingenuity and perseverance. Also we have brought creatures with us that are used to the cold. We found them on an ice moon a long way from our sun, a place called Port Sol. They have liquid helium for blood. Now we farm them. They can live here, even before the terraforming.'

`How remarkable. But there are already creatures living here.'

`We'll put them in cases,' said Minda. `Or zoos.'

`We, my kind, can live here, on this cold world, without making it warm.'

`Then you'll have to leave,' she snapped.

She reached the outskirts of the city.

It was a gridwork of foundations and low walls, all of it half-buried under a blanket of rock-hard water ice and frozen air. The buildings and roads seemed to follow a pattern of interlocking hexagons, quite unlike the cramped, organic, circle-based design of modern Conurbations on Earth, or the rectangular layout of many older, pre-Qax human settlements.

As she walked along what might once have been a street, the pain in her hands and feet seemed to be metamorphosing to an ominous numbness.

The ghost seemed to notice this. `You continue to lose heat,' it said. `Shivering is no longer enough to warm you. Now your body is drawing heat back from your extremities to your core. Your limbs are stiffening-'

`Shut up,' she hissed.

She found a waist-high fragment of wall protruding from the layers of ice. She brushed at it with her glove; loose snow fell away, revealing a surface of what looked like simple brick. But it crumbled at her touch, perhaps frost-shattered.

She walked on into what might once have been a room, a space bounded by six broken walls. Though there were many rooms close by here - clustered like a honeycomb, closer than would have been comfortable for people - it was hard to believe the inhabitants of this place had been so different from humans.

She wondered what it had been like here, before.

Once, Snowball had been Earth-like. There had been continents, oceans of water, and life - based on an organic chemistry of carbon, oxygen and water, like Earth life, and it had worked to create an atmosphere of oxygen and nitrogen, not so dissimilar to Earth's. And there had been people here: people who had built cities, and breathed air, and perhaps gazed at the stars.

But the long afternoon of this world had been disturbed.

Its sun had suffered a chance close encounter with another star. It was an unlucky, unlikely event, Minda knew; away from the Galaxy's centre the stars were thinly scattered. As the interloper fell through the orderly heart of this world's home system, there must have been immense tides, ocean waves that ground cities to dust, and earthquakes, a flexing of the rocky crust itself.

And then, at the intruder's closest approach, Snowball was slingshot out of the heart of its system.

The home sun had receded steadily. Ice spread from polar caps across the land and the oceans, until much of the planet was clad in a thick layer of hardening water ice. At last the very air began to rain out of the sky, liquid oxygen and nitrogen running down the frozen river valleys to pool atop the vast ice sheets, forming a softer snow metres thick.

She wondered what had become of the people. Had they retreated underground into caves? Had they fled their planet altogether - perhaps even migrated to new worlds surrounding the wrecking star?

`This world itself is not without inner heat,' the ghost said softly. `The deep heart of a planet this size would scarcely notice the loss of its sun.'

`The volcano,' Minda said dully.

`Yes. That is one manifestation. And vents of hot material on the spreading seabed have even kept the lower levels of the ocean unfrozen. We believe there may still be active life forms there feeding on the planet's geothermal heat. But they must have learned to survive without oxygen . . .'

`Do you have that on your world? Deep heat, water under the ice?'

`Yes. But my world is small and cold; long ago it lost much of its inner heat.'

`The world I come from is bigger than this frozen ruin,' she said, spreading her arms wide. `It has lots of heat. And it is a double world. It has a Moon. I bet even the Moon is bigger than your world.'

`Perhaps it is,' the ghost said. `It must be a wonderful place.'

`Yes, it is. Better than your world. Better than this.'

`Yes.'

She was very tired. She didn't seem to be hungry, or thirsty. She wondered how long it was since she had eaten. She stared at the frozen air around her, trying to remember why she had come here. An idea sparked, fitfully.

She got to her knees. She could feel the diamond grid of the suit's heating elements press into the flesh of her legs. She swept aside the loose snow, but beneath there was only a floor of hard water ice.

`There's nothing here,' she said dully.

`Of course not,' the ghost said gently. `The tides washed it all away.'

She began to pull together armfuls of loose snow. Much of it melted and evaporated, but slowly she made a mound of it in the centre of the room.

`What are you doing?'

`Maybe I can breathe this stuff.' She knew little about the flitter's systems. Maybe there was some hopper into which she could cram this frozen air.

But the ghost was talking to her again, its voice gentle but persistent, unwelcome. `Your body is continuing to manage the crisis. Carbohydrates which would normally feed your brain are now being burnt to generate more heat. Your brain, starved, is slowing down; your coordination is poor. Your judgement is unreliable.'

`I don't care,' she growled, scraping at the frozen air.

`Your plan is not likely to succeed. Your biology requires oxygen. But the bulk of this snow is nitrogen. And there are trace compounds which may be toxic to you. Does your craft contain filtering systems which-'

Minda drove her suited arm through the pile of air, scattering it in a cloud of vapour. `Shut up. Shut up.'

She walked back to the flitter. By now it felt as if she was floating, like a ghost herself.

The silver ghost told her about the world it came from. It was like Snowball, and yet it was not.

The ghosts' world was once Earth-like, if smaller than Earth: blue skies, a yellow sun. But even as the ghosts climbed to awareness their sun evaporated, killed by a companion pulsar. It was a slower process than the doom of Snowball, but no less lethal. The oceans froze and life huddled inward; there was frantic evolutionary pressure to find ways to keep warm.

Then the atmosphere started snowing.

The ghosts had gathered their fellow creatures around them and formed themselves into compact, silvered spheres, each body barely begrudging an erg to the cold outside. Finally clouds of mirrored life forms rolled upwards. The treacherous sky was locked out - but every stray wisp of the planet's internal heat was trapped.

Minda wondered if this was true, or just some kind of creation myth. But the murmuring words were comforting.

`My home Conurbation is near a ruined city. A bit like this one. The ruin is an old pre-Occupation city. It was called Pah-reess. Did you know that?'

`No. It must be a wonderful place.'

She found she had reached the flitter. She was so cold she wasn't even shivering any more. It was almost comfortable.

She couldn't lie on the ground. But she found a way to use bits of debris from the flitter, stuck in the ice, to prop herself up without having to lean on anything. After a time it seemed easier to leave her eyes closed.

`Your body is losing its ability to reheat itself. You must find an external source of heat. You will soon drift into unconsciousness . . .'

`I'm in my eighth cadre,' Minda whispered. `You have to move cadres every two years, you know. But I was chosen for my new cadre. I had to pass tests. My best friend is called Janu. She couldn't come with me. She's still on Earth . . .' She smiled, thinking of Janu.

She felt herself tilting. She forced open her eyes, frost crackling on her eyelashes. She saw that the pretty, silvered landscape was tipping up around her. She was falling over. It didn't seem to matter any more; at least she could let her sore muscles relax.

Somewhere a voice called her: `Always protect your core heat. It is the most important thing you possess. Remember . . .'

There was something wrong with the silver ghost, she saw, through sparkling frost crystals.

The ghost had come apart. Its silvery hide had unpeeled and removed itself like a semi-sentient overcoat. The hide fell gracelessly to the frozen ground and slithered towards her.

She shrank back, repelled.

What was left of the ghost was a mass of what looked like organs and digestive tracts, crimson and purple, pulsing and writhing, already shrivelling back, darkening. And they revealed something at the centre: almost like a human body, she thought, slick with pale pink fluid, and curled over like a foetus. But it, too, was rapidly freezing.

All around the subsiding sub-organisms, the frozen air of Snowball briefly evaporated, evoking billowing mist. And the dormant creatures of the Snowball enjoyed explosive growth: not just lichen-like scrapings and isolated flowers now, but a kind of miniature forest, trees pushing out of the ice and frosted air, straining for a black sky. Minda saw roots tangle as they dug into crevices in the ice, seeking the warmth of deeper levels, perhaps even liquid water.

But in no more than a few seconds it was over. The heat the ghost had hoarded for an unknown lifetime was lost to the uncaring stars, and the small native forest was freezing in place for another millennium of dormancy. Then the air frosted out once more.

At last Minda fell.

But there was something beneath her now, a smooth, dark sheet that would keep her from the ice. She collapsed onto it helplessly. A thick, stiff blanket stretched over her, shutting out the starry sky.

She wasn't warm, but she wasn't getting any colder. She smiled and closed her eyes.

When she opened her eyes again, the stars framed a Spline ship, rolling overhead, and the concerned face of her cadre leader, Bryn.

The Spline rose high, and the site of Minda's crash dwindled to a pinpoint, a detail lost between the tracery of the abandoned city and the volcano's huge bulk.

`It was the motion of the vegetation that our sensors spotted,' Bryn said. Her face was sombre, her voice tired after the long search. `That was what drew us to you. Not your heat, or even your ghost's. That was masked by the volcano.'

`Perhaps the ghost meant that to happen,' Minda said.

`Perhaps.' Bryn glanced at the ghost's hide, spread on a wall. `Your ghost was astonishing. But its morphology is a logical outcome of an evolutionary drive. As the sky turned cold, living things learned to cooperate, in ever greater assemblages, sharing heat and resources. The thing you called a silver ghost was really a community of symbiotic creatures: an autarky, a miniature biosphere in its own right, all but independent of the universe outside. Even the skin that saved you was independently alive . . . This is a new species for us. Evidently we have reached a point where two growing spheres of colonisation, human and ghost, have met. Our future encounters will be interesting.'

As the planet folded on itself, Minda saw the colony of the ghosts rising over the chill horizon. It was a forest of globes and half-globes anchored by cables; gleaming necklaces swooped between the globes. The colony, a sculpture of silver droplets glistening on a black velvet landscape, was quite remarkably beautiful.

But now a dazzling point of light rose above the horizon, banishing the stars. It was a new sun for Snowball made by humans, the first of many fusion satellites hastily prepared and launched. The ghost city cast dazzling reflections, and the silver globes seemed to shrivel back.

Bryn said, watching her, `Do you understand what has happened here? If the ghosts' evolution was not competitive as ours was, they must be weaker than us.'

`But the ghost gave me its skin. It gave its life to save me.'

Bryn said sternly, `It is dead. You are alive. Therefore you are the stronger.'

`Yes,' Minda whispered. `I am the stronger.'

Bryn eyed her with suspicion.

Where the artificial sun passed, the air melted, pooling and vaporising in great gushes.

After that first contact, two powerful interstellar cultures cautiously engaged. One man, called Jack Raoul, played a key role in developing a constructive relationship.

To understand the creatures humans came to know as `Silver Ghosts' - so Raoul used to lecture those who were sceptical about the mission that consumed his life - you had to understand where they came from.

After the Ghosts watched their life heat leak away to the sky, they became motivated by a desire to understand the fine-tuning of the universe. As if they wanted to fix the design flaws that had betrayed them.

So they meddled with the laws of physics. This made them interesting to deal with. Interesting and scary.

Relationships deepened. The `Raoul Accords' were established to maintain the peace, and give humans some say in the Ghosts' outrageous tinkering with the universe.

But times changed. The Coalition tightened its grip on human affairs.

Three centuries after Minda, there was rising friction between Ghost and human empires. And Jack Raoul found himself out of favour.

THE COLD SINK

AD 5802

`I called on Jack Raoul at the time appointed, acting in my capacity as a representative of the Supreme Court of the Third Expansion. Raoul submitted himself to my custody without complaint or protest.

`I must record that the indignity of the armed escort, as ordered by the court, only added to the cruelty of the procedure I was mandated to perform.'

It was as if somebody had called his name.

He was alone in his Virtual apartment - drinking whisky, looking out at a fake view of the New Bronx, missing his ex-wife - alone in a home become a gaol, in fact. Now he looked to the door.

Maybe they'd come to get him already. He felt his remote heart beat, and his mood of gloomy nostalgia gave way to hard fear. Don't let 'em see they've won, Jack.

With a growl, he commanded the door to open.

And there, instead of the surgeons and Commission goons he had expected, was a Silver Ghost: a spinning, shimmering bauble as tall as Raoul, crowding the dowdy apartment-block corridor. It was intimidating close to in this domestic environment, like some huge piece of machinery. In its mirrored epidermis he could see his own gaunt Virtual face. An electromagnetic signature was quickly overlaid for him - Ghosts looked alike only in normal human vision - but he would have recognised his visitor anyhow.

`You,' he said.

`Hello, Jack Raoul.' It was the Ghost known to humans as the Ambassador to the Heat Sink. Raoul had dealt with this one many times before, over decades.

`What are you doing here? How did you get past the Commission security? . . . Ambassador, I'm afraid I'm not much use to you any more.'

`Jack Raoul, I am here for you.'

Raoul grimaced. What in Lethe did that mean? `Look, I don't know how closely you've been following human politics. This isn't a good day for me.'

`As in former times, you hide your emotions behind weak jokes.'

`They're the best jokes I've got,' he said defensively.

`The truth is well known. Today you must face the sentence of your conspecifics.'

`So you're here for the spectacle?'

The Ghost said, `I am here to present another option, Jack Raoul.'

Raoul studied the Ghost's bland, shimmering surface. There was no hope for him, of course. But he felt oddly touched. `You'd better come in.'

The Ambassador sailed easily into the apartment, making the walls crumble to pixels where its limbs brushed against them. `How is the whisky today?'

Raoul sipped it, savouring its peaty smoke. `You know, I'm more than two hundred years old. But I figure that I could live another two hundred and not get this stuff right.' Still, maybe this would be his lasting legacy, he thought sourly: the best Virtual whisky in all the Third Expansion, savoured and remembered long after the Raoul Accords had been forgotten - which time might not be so far into the future.

`You are missing Eve,' said the Ambassador.

The Ghost's perception had always surprised him. `Yeah,' he admitted. `In a way this place is all I have left of her. But even here she is just an absence.'

`You must leave her now,' said the Ghost. `Come with me.'

The abruptness of that startled him. `Leave? How? Where are we going?'

`Jack Raoul, do you trust me?'

Escape was impossible, of course; Coalition security was tight, the Commission omnipresent. But this lunatic Ghost must have come a long way for this stunt, whatever it was. Maybe it was only respectful to go along for the ride.

Anyhow, what did he have to lose? One last adventure, Jack: why not?

He put the whisky glass down on a low table, savouring the weight of the heavy crystal, the gentle clink of its base on the table. `Yes,' he said, looking into his heart. `Yes, I guess I do trust you.' He stood straight. `I'm ready.'

Again he had the sensation that somebody was calling his name.

The room crumbled into blocky pixels that washed away like spindrift, and suddenly he was suspended in light.

`It is important to understand that Raoul's fully human brain was maintained by normal physiological functions. Think of him as a human being, then, flensed and de-boned, sustained within a shell of alien artifice.

`The operation was more like a dismantling than a medical procedure. It was rapid.

`Immediately after the beheading I lifted the head and observed Raoul's eyes.

`The lids worked in irregularly rhythmic contractions for about five or six seconds. Then the spasmodic movements ceased. The face relaxed, the lids half-closed on the eyeballs, leaving only the white of the conjunctiva visible. (It will be recalled that Raoul's "eyes" were quasi-organic Ghost artefacts.)

`I called in a sharp voice: "Jack Raoul!" I saw the eyelids lift up, without any spasmodic contractions.

`Raoul's eyes fixed themselves on mine.'

Raoul looked down at himself. His body gleamed, a silver statue.

He peered around, trying to get oriented. He made out a tangle of silvery rope, a complex, multi-layered webbing that appeared to stretch around him in all directions. Everywhere he looked, Ghosts slid along the cables like droplets of mercury. And beyond and through it all, a deep glimmering light shone, a universal glow made pearl grey by the depth of the tangle.

He sure wasn't on 51 Pegasi I-C any more.

Jack Raoul had spent his working life at the uneasy political interface between Ghost and human. In those vanishing days of more-or-less friendly rivalry, governed by more-or-less equable accords, it had been Raoul's responsibility to ensure that humans knew what the Ghosts were doing, on their vast, remote experimental sites, just as Ghost observers were allowed to inspect human establishments. Mutual security through inspection and verification, an old principle.

But Raoul had soon learned that asking for evidence wasn't enough. Somebody had to go out there and see for himself - and on Ghost terms. That meant a sacrifice, though, that nobody was prepared to accept.

Nobody but Raoul himself.

So his brain and spinal cord were rolled up and moved into a cleaned-out chest cavity. His circulatory system was wrapped into a complex mass around the brain pan. The Ghosts built a new metabolic system, far more efficient than the old and capable of working off direct radiative input. New eyes, capable of working in spectral regions well beyond the human range, were bolted into his skull. He was given Ghost `muscles' - a tiny antigravity drive and compact actuator motors. At last he was wrapped in something that looked like sheets of mercury.

Thus he was made a Ghost.

Jack Raoul couldn't live with people any more, outside of Virtual environments. Not that he wanted to. But he could fly in space. He could eat sunlight and survive the vacuum for days at a time, sustaining his antique human core in warmth and darkness. It was odd that he was actually more at home here in a Ghost ship than anywhere in the human Expansion.

`. . . Jack Raoul.' The Sink Ambassador swum before him, spinning languidly. `How do you feel?'

Raoul flexed his metal fingers. `How do you think I feel?'

`You are as evasive as ever.'

`Am I on a ship, Ambassador?' If so it was bigger than any Ghost cruiser he had ever seen.

`In a manner of speaking. For now, we must ascend.'

`Ascend?'

`Towards the light. Please.' The Ghost rose, slow waves crossing its surface.

Effortlessly Raoul followed.

Soon they were passing into the tangle of silvery ropes. When he looked back, there was nothing to mark the place he had emerged from - not even a hollow in the tangle.

At home or not, he knew he shouldn't be here.

`Ambassador, I was under house arrest. How did you get me out of there?'

`Have you improved your understanding of quantum physics since we last met?'

Inwardly, Raoul groaned.

The Ambassador began, somewhat earnestly, to describe how the Ghosts had learned to break up electrons: to divide indivisible particles.

`The principle is simple,' said the Ghost. `An electron's quantum wave function describes the probability of finding it at any particular location. In its lowest energy state, the wave function is spherical. But in its next highest energy state the wave function has a dumb-bell shape. Now, if that dumb-bell could be stretched and pinched, could it be divided? . . .'

The Ambassador described how a vat of liquid helium was bathed in laser light of a precise frequency, exciting electron wave functions into their dumb-bell configurations. Then, as the pressure within the helium was increased, the electron dumb-bells split and pairs of half-bubbles drifted apart.

To Raoul it sounded like a typical Ghost experiment: extremes of low temperature, the fringe areas of physical law.

`Jack Raoul, you must understand that the quantum wave function is no mathematical abstraction, but a physical entity. We have split and trapped a wave function itself - perhaps the first time in the history of the universe this has occurred,' the Ghost said immodestly.

Raoul suppressed a sigh. `You guys never do anything simply, do you? So you split an electron's wave function. So what?'

`The half-electrons, coming from the same source, are forever entangled. Put another way, if the bubbles are separated and the wave function collapsed, an electron can leap from one bubble to another . . .'

Raoul fought his way through that fog of words. `Oh,' he said. `Teleportation. You're talking about a new kind of teleportation. Right? And that's what you used to get me out of my cell.'

`Yes. Time was short, Jack Raoul. Your conspecifics were closing in.'

So they were, and so they had been for decades.

Still they rose through the crowded tangle. That all-consuming light seemed, if anything, to be growing brighter. He could sense deep vibrations passing through the ship's structure, the booming low-frequency calls of Silver Ghosts. Here and there he saw denser concentrations - nurseries, perhaps, or control centres, or simply areas where Ghosts lived and played - little more than patches of silvery shadow, like birds' nests in the branches of some vast tree. It was characteristic Ghost architecture, vibrant, complex, beautiful, alive - and totally inhuman.

It had always seemed to Jack Raoul that humans and Ghosts were different enough that everybody could get along. Their goals were utterly unlike humanity's, after all. That had been the motivation behind the patchwork of treaties eventually known as the Raoul Accords. But times changed.

When Raoul was a boy, the human colonisation programme was still piecemeal, driven by individual initiative. The leading edge of the Third Expansion had been too remote from the centre, Earth, to be tightly controlled. Players like Jack Raoul had freedom of movement. But gradually the Coalition - especially its executive arm the Commission for Historical Truth - had infiltrated all mankind's power centres. The ideologues of the Coalition had provided the species with a unity of purpose, belief, even language. The Third Expansion became purposeful, a powerful engine of conquest.

But from Jack Raoul's point of view, it was all downside. The pro-human ideology grew ferocious. Soon even longevity, like Raoul's, was seen as a crime against the interests of the species. As the short generations had ticked by, and as the worlds of humanity filled up with fifteen-year-old soldiers, Raoul had come to feel like a monument left standing from an earlier, misunderstood era.

And it got worse.

Raoul had been summoned back to Earth, to appear before the Commission for Historical Truth. It was part of the great cleansing that had been pursued ever since the days after the fall of the Qax Occupation of Earth, when collaborators had been hunted down and judged. After a curt hearing, Raoul's life's work had been retrospectively labelled as counter to the evolutionary interests of mankind.

His advisers had urged him to appeal. Everything he had done had been under the specific direction of legally constituted governments and inter-governmental bodies of the time. But he wasn't about to justify himself to a bunch of children. He knew the true value of his legacy. After all, it had cost him his own humanity.

And so sentence had been passed.

`How did you and I get to be the bad guys, Ambassador?'

The Ambassador's perfect hide cast glimmering highlights from the tangle sliding past them. `We are old, Jack Raoul. Old and out of our time.'

`That we are, my friend.'

`Nevertheless, Jack Raoul, you have been a valuable interface between our species. Many sentient beings were saved from unhappiness and premature termination by your actions. This "punishment" is absurd and disproportionate. It is probably not even legal in your own terms.'

`You're storing up trouble,' Raoul said. `Like it or not, I was tried by humanity's highest court. If you intervene it will surely go badly for you; the Coalition is not noted for its forgiveness. As for me, maybe it's my duty to sit tight and take my punishment. I will be the greater martyr for it.'

`See what we offer you, Jack Raoul, before you turn it down for the sake of martyrdom.'

At last, Raoul saw, their steady rise was slowing, the tangle of silver cables thinning out, as if they were reaching the top of a vast metallic tree. But there was still no sign of black, star-studded sky above; rather he made out swathes of light, glowing brightly, bright as the sun. Maybe the ship was actually sailing through the outer layers of a sun; it wouldn't be the first time the Ghosts had pulled such a stunt.

But the light, so his smart eyes quickly told him, was too complex for that. It was as if the sky was crowded with stars, every place he looked.

And suddenly he understood. Olbers' paradox . . .

`Sink Ambassador. This teleportation technique of yours. It can carry you from one side of the universe to the other. Yes?'

`Further than that.'

`And the light that bathes us-'

`It is starlight, Jack Raoul. Nothing but starlight.'

Again he had the sense that someone called him. He ascended into the light, seeking the voice.

`After several seconds the eyelids closed again, slowly and evenly, and the eyes took on the same appearance as before.

`I called out again.

`Once more, without any spasm, the lids lifted. Undeniably living eyes fixed themselves on mine with perhaps even more penetration than the first time. Then there was a further closing of the eyelids, but now less complete.'

He looked down at the Ghost ship, a mass of entwined silvery cables with knots of life embedded everywhere, all of it glowing in the endless starlight. He could still make out the Sink Ambassador, a mercury droplet clinging to the tangle.

But the structure was shrinking, closing on itself. The sky was a sphere of light, glowing white, and he felt he was being drawn away from the tangle, up into the light.

`Olbers' paradox,' he whispered.

`Yes,' said the Ghost. `A key moment in the evolution of human thought, a philosophical fossil preserved by exiles through the Qax Extirpation . . . If the universe were infinite and static, every line of sight would meet the surface of a star, and the whole sky would be as bright as the surface of a sun. Even occluding dust clouds would soon become as hot as the stars themselves. That was evidently not so, observed those thinkers of old Earth. Therefore their universe could not be infinite or static.'

`But here-'

`But here, things are different. This appears to be a pocket universe, Jack Raoul. We believe it is a bubble of spacetime pinched off by a singularity. The heart of a black hole, perhaps.'

`Infinite and static.'

`Yes.'

`It doesn't make sense,' Raoul said. `If the whole sky is as hot as the surface of the sun - Ambassador, how do you keep cool?'

The Ghost rolled, shimmering. `There is another pocket universe at the centre of the colony. Our heat is dumped there.'

Raoul gaped. `You have a whole universe for a heat dump? And is that how the stars keep shining?'

`We think so. Otherwise, immersed in this heat bath, simple thermodynamics would soon cause the stars to evaporate. We have only recently arrived here, Jack Raoul; there is much we have yet to explore. But it is clear to us that this cosmos is heavily engineered.'

`Engineered? Who by?'

`The Xeelee,' the Ghost said.

`Ah.' The Xeelee: aloof from the petty squabbles of lesser kinds, even of sprawling, brawling humanity. The Xeelee, as remote as clouds.

`It is not certain,' said the Ghost. `But there are certain signatures we have come to recognise . . . Such universe-modelling does appear to be a characteristic Xeelee strategy.'

Raoul laughed, wondering. `At last you've found yourselves an inverted sky, Ambassador. A Cold Sink.' Considering their evolutionary history, shaped by cosmic betrayal and cold, this place was like a Ghost wish-fulfilment fantasy.

`Yes. Jack Raoul, we believe we were led here, by the Xeelee. Perhaps they have prepared a bolt-hole of their own, in case their epochal war with the photino birds is ultimately lost.'

`You see this place as a bolt-hole? What are you hiding from?'

`You,' said the Ambassador.

That took him aback.

`Jack Raoul, your Expansion is already expanding exponentially. We are in your way.'

Raoul had heard this said. The Ghosts' home range lay between mankind and the rich fields of the Galaxy's Core, and the Expansion was pressing.

But he protested, `It's a big Galaxy. It's not even as if we are fighting over the same kinds of territory, or resource. Ghosts are adapted to the cold and dark, humans to deep gravity wells. There is room for all of us.'

`That is true,' said the Ambassador. `But irrelevant. Your Expansion is fuelled by ideology as much as resource acquisition - and it is not an ideology that preaches of sharing. In such a situation there can be no diplomacy.

`There is already war. A series of flashpoints, all along the Expansion's growing border. Naturally we will use our every resource in our fight for survival, just as we did when our sun died. There will be epic battles. But the logic is against us. Our most optimistic projection is three thousand years.'

`Until what?'

`Until the Silver Ghosts are extinct.'

Raoul said grimly, `I spent my life fighting against such outcomes, Ambassador. As did you. Are you telling me now it was all futile?'

`From the beginning. But there is no failure, Jack Raoul. Here we have found a sanctuary. Though the Xeelee do not intervene in the squabbles of lesser types like us, they appear to embrace diversity. They gave us this place. Perhaps they have prepared a haven for your kind, against the inevitable day when humanity too must decline.'

But Raoul found it increasingly hard to concentrate; his attention was drawn away from the Ghost and his words, away from the tangle, up to that infinite light.

The Ghost spun on its invisible axis, this way and that. `Jack Raoul, I urge you to consider. If we are safe here, so are you. We can provide any Virtual environment you desire.' The Ghost seemed to hesitate. `We can give you Eve.'

Ah, Eve . . .

You can `t stay. It was as if he could hear her voice, see her pushing her fingers through her greyed hair. You held on to me for too long. And now, this. You never could let go Jack. But now you have to. You see that, don't you?

He felt himself rise further. The tangle shrank beneath him, becoming lost in the light.

It's time to go, Jack.

`The Sink Ambassador is a friend,' he told Eve.

`Jack Raoul?'

Sure he's a friend. That's why he's showing you what you want to see. You don't want to die a failure. But it isn't real. You know that, don't you?

Perhaps the Sink Ambassador somehow heard this inner voice. `Jack Raoul, it can be as real as you desire. We have only a single moment to give you. But we can make that moment last an eternity.'

`Thank you, my friend. But this isn't my place.'

`Jack Raoul, please . . .'

The tangle faded into the light. Raoul had time for a last, brief stab of regret.

Then, artificial eyes raised, he ascended into the white glow that was calling him.

`I attempted a third call, but there was no further movement. The eyes finally took on the glazed look of the dead.

`The whole sequence of post-excision events lasted twenty-five to thirty seconds. More precise timings are of course available in the record.

`Death occurred due to separation of the brain and spinal cord, after transection of the surrounding tissues and excision of the brain from the chest cavity, which probably caused acute and possibly severe pain. Consciousness was lost due to a rapid fall of intracranial perfusion of blood. Throughout the procedure nervous connections were maintained with sensory organs, notably the "eyes", "ears" and "nose".

`As noted, Jack Raoul did not resist.

`It may be that because of Raoul's unique physical condition, this "beheading" was the only available mode of execution. However I believe that my precise observations during my administration of this case demonstrate that Raoul was aware of what was happening to him even after excision, thus casting doubt on the humanity of the procedure.

`I will concede that I saw a certain peace, at the last, in Jack Raoul's dying eyes. It may be that somehow he found consolation, which may in turn give comfort to those who passed sentence on this complex man.

`Death occurred at the time and place noted.

`Signed: HAMA TINIF, Attending Physician.'

The Sink Ambassador was right. War was inevitable. The logic of the Third Expansion would have it no other way.

At first human forces made spectacular advances. The Ghosts, capable of manipulating physical law, were on paper formidable adversaries. But we were better at making war.

In the centuries of conflict that followed, the Coalition completed its control. Humanity's ideology and economics were reoriented. Our entire civilisation became a machine to serve the Expansion and the war, and in turn became dependent on those two projects.

But then, as we approached the Ghosts' home ranges, the Expansion stalled.