Xeelee: Endurance

by Stephen Baxter

  There were two types of particles: fermions, the building blocks of matter, like quarks and electrons, and force carriers, like photons. The principle of supersymmetry had it that each building block could be translated into a force carrier, and vice versa.

  ‘The supersymmetric twins, the s-particles, are inherently fascinating, if you’re a physicist, which I’m not,’ said Samm. ‘But the magic comes when you do two supersymmetric transformations – say, electron to selectron and back again. You end up with an electron, of course – but an electron in a different place . . .’

  ‘And that’s the Susy drive.’

  ‘Yep. A principle even the Ghosts have never explored, it seems. According to the Sink Ambassador anyhow. Well, Joens Wyman pumped his money into this thing, and got as far as a working prototype. But in those days nobody would invest in human research and development; it was always easier and cheaper to buy alien tech off the shelf. Joens hoped to cut his losses by sending his Susy-drive ship in search of treasure nobody else could get to.’

  ‘The quagma. What happened?’

  ‘Joens finished up with nothing but the Susy drive and the clothes he stood up in. He fled his creditors—’

  ‘And he came here.’

  ‘Yes. Good place to hide – anyhow, it was then. His son married into your mother’s family, who owned the Miriam.’

  ‘And he lodged the Susy drive on the hull of the ship.’

  ‘Yeah. So it’s come down the generations. My father told me about it, and gave me the data on this slate. I think Joens always thought this old monster might be useful as a last resort. Well, he was right.’

  Donn stared at his father. This was a side of him Donn hadn’t seen before, this decisive adventurer. But maybe no son saw that in his father. ‘You’re not serious. You’re not planning to fire up this Susy drive, this two-hundred-year-old disaster?’

  ‘You have a better idea?’

  ‘When was it last tested?’

  ‘When do you think? Look, according to these displays the field it generates will envelop the whole of the Reef. We’ll get out of here, all of us. And then you and I will go down to Minda’s Saviour, and drink free Poole’s Blood for the rest of our lives.’

  ‘If it works. And if it doesn’t work?’

  ‘Then what have we lost?’ He tapped the screen. It switched to the external image. Panels blew out from the black casing fixed to the base of the pod; a zoomed-in view showed them the jewelled guts of the Susy drive.

  Then the data slate chimed an alarm. The Susy-drive display cleared, to reveal an image broadcast from the Coalition monitor drone. An image of an exploding star.

  ‘Damn,’ said Samm. ‘I didn’t imagine it would be so quick.’

  ‘Father, look.’ The explosion was strongly asymmetrical, a flower of ugly light splashed across the slate. And there was a denser knot to one side of the supernova.

  Samm tapped the screen, overlaying analyses of mass density and velocity vectors. ‘That’s the neutron star. The core of the Boss. It’s been spat out of there like an apple seed – thousands of kilometres a second.’ He brought up a Galactic display. ‘Look at that. It’s been fired straight out of the Association towards the Sagittarius Arm.’

  ‘The Ghost home range.’ Green asterisks began to appear around the fleeing neutron star. ‘What’s that?’

  ‘Ghost technology . . . Ghost ships, popping up out of nowhere. Settling into orbit around that neutron star. And, wow, look at that.’ A major green anomaly. ‘It has to have the mass of a planet.’

  ‘The Ghostworld.’

  ‘Looks like it. How are they bringing all this to the neutron star?’

  Donn said, ‘Just by making it more likely that the planet should be in orbit around the neutron star than wherever it used to be . . .’

  ‘What?’

  ‘Never mind. Father, we need to get out of here.’

  Samm brought back the Susy display and began to scroll through outputs. ‘Let’s just hope this damn Susy drive does what I tell it to.’

  ‘Father – don’t you know?’

  ‘I told you. It’s kind of unreliable, or so my father told me. We ought to end up just a little above the Galactic plane, however. OK, it’s ready.’

  ‘As quickly as that?’

  ‘Well, that supernova shock wave is going to take a while to get here – years, as we’re light years off from the Boss. But we can’t expect rescue for years either, even if the Coalition is willing to try; the gravity waves from the detonation are going to churn up hyperspace for a long time. Best to get out of here now if we can – and if this doesn’t work, we might have time to figure out something else. I’ve sent an alarm out through the Reef.’

  ‘Shouldn’t we ask Mother first?’

  ‘She’d only say no. Hang onto that rail. Good luck, son!’ He stabbed a finger at his data slate.

  The Association stars turned to streaks and disappeared.

  So, just as his father had tried to explain, Donn was leapfrogged through Susy-space. What he hadn’t been told was what it would feel like.

  Susy-space was another universe, laid over Donn’s own. It had its own laws. He was transformed into a supersymmetric copy of himself – an s-ghost in Susy-space. And it was . . . different. Things were blurred. Susy-space cut through the distinction between Donn, here, and the stars, out there. Donn could feel the scale of the journey, as if the arch of the universe were part of his own being. Distance crushed him.

  But at last it was done.

  The Reef of ships popped out of Susy-space, sparkling with selectrons and neutralinos.

  Samm and Donn stared at each other. ‘Let’s not do that again,’ said Donn.

  ‘Agreed.’ Samm tapped his data slate to get an external view.

  No stars. Just darkness, broken only by the faintest smudges of grey light.

  ‘Are they galaxies?’ asked Donn.

  ‘Oops,’ said Samm.

  Humans spread across the stars, their capability increasingly rapidly, their zone of influence expanding at many times light-speed.

  A period known as the Assimilation followed, in which the wisdom and power of other species were absorbed, on an industrial scale. Those they conquered became mere resources: even the last traces of those pushed into extinction, like the Silver Ghosts, were exploited.

  Soon, only the Xeelee stood between humans and dominance of the Galaxy, and beyond.

  And all the time, as humans belatedly learned, the Xeelee were waging war on another front, against a cosmos-wide force that was wrecking the stars themselves.

  The Xeelee war had its own terrible logic. Eventually the tide turned against humanity.

  The conflict had lasted a million years. There were many casualties.

  GRAVITY DREAMS

  AD 978,225

  1

  ‘Massive sensor dysfunction!’

  This time his own shout dragged Coton out of his dreams. He lay on his pallet, gasping, sweat coating his face.

  ‘It’s all right.’ Here was his grandmother, Vala, in her night robe, her round, calm face shadowed in the glow cast by a single hovering light globe. Above him loomed the frame of Vala’s house, a tetrahedron of metal bars and panels hung with musty tapestries, cosy and cluttered and mundane. ‘You woke yourself up.’

  ‘And you. I’m sorry.’

  ‘Don’t be.’ She sat on his pallet and passed her hand over his brow. Her fingertip traced the tattoo there, an inverted black tetrahedron, like her own. ‘It’s why you came here, in a way. So I can help you cope with the nightmares.’

  ‘But it wasn’t like my other dreams.’ He’d had plenty of nightmares of flight. It was only a month since the ships of the Second Coalition had appeared in the skies of Centre, and the officials and the troops had landed to impose their curfews and tithes and e
vacuations – and the population, enraged, had turned in on itself, and Weaponised families like Coton’s had become targets of hate and frustration. Only a month since he’d had to abandon his parents, and his world, at the age of seventeen.

  ‘But this was different.’ He clenched his fists and huddled them into his chest. ‘I couldn’t move. As if my arms and legs had been cut off. I could see and hear, but there was something wrong with my head. I was floating in this big sky, a red sky that was full of glowing shapes, like light globes – or stars. But I hated it, for it was wrong.’

  ‘Wrong?’

  ‘I shouldn’t have been there. It was my duty to get everyone out – to get them home. But I couldn’t move.’ He twisted, as if wrapped up.

  She took his hands. ‘There could be another cause. Your parents would have explained all this, one day . . . You know we’re Adepts, Coton, don’t you? And young Adepts sometimes have dreams – we call them gravity dreams. It might be nothing to do with the pogroms back on Centre . . . But dreams of immobility are common even among normals, I think. These things are subtle, indirect. Your dream could be a sign that you’re healing, in some way. The waking mind trying to reconnect with the body.’

  ‘What did I say?’

  ‘When you woke up? Not words I recognised. Mas-eef . . . Can you replay?’

  Coton’s own voice came echoing out of the air, the sound shaped by the smart systems that pervaded Vala’s environment. ‘Ma-seef senss-or dees-funx-eon.’

  ‘Doesn’t mean anything,’ Coton said.

  ‘Perhaps not. The words sound archaic. It might be interesting to check.’

  That was just like his grandmother, whose scholarship, according to his own mother, had made her a cold parent, and caused them to fall out. Her own world, this world, after all, had no name but a numbered label – Delta Seven – and Vala referred to it, not as home, but as ‘the college’. Now he was stuck here with her, and she was studying his dream as if it was an academic puzzle.

  He felt a surge of resentment. He needed to move, to blow away the last dark shreds of his nightmare. He pushed aside the sheets and rolled off his pallet, his bare feet on the cool floor.

  ‘Are you all right?’

  ‘I need some water.’

  He shoved his way out through the thick woven flap that was the door of the house, and emerged into cavernous gloom. ‘Lights.’ A sprinkling of globes lit up and revealed the expanse of this Map Room, the shining floor, the complicated walls with their reefs of shelving, and the alcoves folding off into the dark like suppressed memories.

  He made for a bathroom block, a neat cube a hundred paces away. Here there were spigots and low sinks. He bent, and the water, flowing without a command, poured into his mouth, cool and clean.

  When he was quenched he stood back, and found himself staring at the spigot.

  Vala walked to his side, wrapped in a black cloak, evidently uncertain of his mood. She saw what he was staring at. ‘You know, that spigot was put here for the scholars who once worked in this chamber. Now the students are long gone. But the spigot itself, the tip of a vast self-maintaining system, doesn’t care whose thirst it quenches; it just does its job, millennium after millennium. I’m sure there’s a lesson for us all in that . . .’

  He glanced back at her shack, sitting squat on the shining floor of this immense building. ‘Long gone?’

  ‘Oh, yes. It’s obvious my house is much more recent than the Map Room itself. When I first moved in I could even see traces of a hearth. Somebody had been building fires, here on the floor of the Room. That’s how badly things fell apart, when the last unified government collapsed. And this is what the worlds of mankind are like, all across the Galaxy – or at least the part of it we still inhabit. We are a lesser generation, squatting in the ruins of a greater past. Lighting fires on the marble floors of libraries.’

  They walked together across the gleaming floor, their voices small in the huge hall. ‘What did they study here?’

  ‘You know, you’ve been here a month, and this is the first time you’ve shown any real curiosity about this place. I think that’s a good sign, don’t you?’

  But he had no wish to be analysed, and he kept silent until she answered his question.

  ‘The truth is, I’m not sure. The archives have been very damaged. The college probably served two main purposes. First it was a branch of the Library of Futures. The architecture is similar to the central Library on Earth.’ She waved a hand. ‘Once, you know, the air in here, those alcoves and shelves, would have been full of Virtual images of space battles, ships hurling themselves against the enemy in sheaves of unrealised possibilities!’

  He barely understood this, but it was a thrilling vision. ‘What enemy?’

  ‘The Xeelee, of course. What other enemy is there? As for the second function – if I’m to show you that, you’ll have to come outside, just briefly.’

  She linked her arm in his, and led him to a walkway that jolted into motion, making Coton stagger. They were swept towards a blank wall at alarming speed. Coton tried not to show his nervousness. All this was grander than anything he was used to on Centre, and more ancient, and he couldn’t help wondering what would happen if the power were to choose today to fail. Vala seemed quite unconcerned.

  In the very last instant the wall puckered and opened, to reveal a gleaming corridor. The walkway swept them inside, and Coton tried not to flinch. They passed along the corridor, and emerged in the open air, on a parapet that rimmed this cubical building, under a star-filled sky. Coton’s bare feet were cold.

  He hadn’t been outside since he’d been dumped here from the Coalition scow – he did recall it had been night then, always night here on this sunless world – and he only vaguely remembered the landscape, the city. Buildings stood proud as far as he could see, most of them intact, in rows and crescents and great overlapping circles. It was like a museum of architecture. But, under a sprinkling of light globes, most of the buildings were dark, and here and there fires flickered. And between the buildings, though some of the moving walkways evidently still ran, vegetation had broken through the ancient pavement and flourished green and black and purple.

  Vala said, ‘You must imagine this university-city as it was in its day, when these lanes were full of flitters and ground vehicles, and Commissaries crowded in their black robes. What a sight it must have been! The college was surely a strategic anchor of the Library of Futures, in this corner of the Sagittarius Arm. And the other purpose was – that!’ She pointed into the sky.

  There was nothing much to be seen just where Vala was pointing – but what a sky it was, Coton thought. Stars hung like crimson lanterns before a veil of wispy, glowing gas, where dense knots told of new stars struggling to shine. But behind all that lay a deeper darkness, a profound night that spanned half the sky. That was the signature of the Xeelee – of the Scourge.

  ‘Do you recognise what you’re seeing? Which way is Sol, for example?’

  He jerked his thumb over his shoulder, away from the Scourge darkness. ‘That way.’

  ‘Yes. About nine thousand light years away, in fact. Sol is in the next spiral arm out from the centre of the Galaxy – and opposite the Scourge, the darkening of the stars. The Xeelee are only a few hundred light years out from us now, and they’ll be here in a millennium or so. Before they pass on towards Sol itself.’

  ‘Not if the Second Coalition can stop them. The Marshals have a plan. The crew told me on the freighter.’

  She snorted. ‘I’d like to hear it . . . As for the young stars, we’re in the Carina nebula, one of the Galaxy’s great stellar nurseries.’

  ‘They won’t last long—’

  ‘No. Even the youngest star in the Galaxy is infested by photino birds. And it is the action of the photino birds that was, I believe, the second subject of the college’s study . . .’

  Pho
tino birds: creatures of dark matter that swarmed in the hearts of stars, subtly manipulating their evolution. Subtly killing the light. Meanwhile the Xeelee, creatures of the light themselves, were opposing them, or trying to. Throughout human history, and for long ages before, a war in heaven had raged, all unobserved by mankind.

  Vala pointed again. ‘Up there is a neutron star. When it was discovered by astronomers on Earth, it was one of the brightest stars in the Galaxy – as massive as a hundred Sols, and a million times as luminous. Its catalogue number was HD93129A.’

  ‘It must have imploded. A supernova—’

  ‘Yes. But it popped too quickly. The photino birds had tinkered! And under the old Coalition, the college was established here to study how that supernova process differed from the usual, whatever might be strange about the remnant neutron star, and whatever could be learned of the birds themselves.’ She smiled, and the coal-black tattoo on her forehead glinted in the red starlight. ‘What a sky! I sometimes think you can see all of human history summarised from this spot – and our future.’

  ‘So why are you here now? You and those you work with.’

  ‘We’re still studying the neutron star – but from a different point of view. We’re looking for relics of a later age.’

  ‘Relics?’

  ‘Weaponised. In the course of the Xeelee war, a post-Coalition government called the Integrality threw a breed of Weaponised humans into neutron stars, so they could turn those stars themselves into engines of war. Direct their flight, so they became like huge cannonballs. There are some in our neutron star, we think.’

  Weaponised people – as Coton was, and his grandmother. ‘What will you do when you find them?’