Eternal Light

by Paul J McAuley

  And then it was past, just like that, and they were flying beneath the rings, kicked into a new course by the close gravitational encounter with the shepherd moon, angled down towards Saturn’s wide curve and the next course change. And Robert Johnson sang:

  All I needs my little sweet woman

  And to keep my company.

  And then there was silence.

  One by one, proximity alarms faded to green.

  There was no sign of the cop. He hadn’t followed.

  Suzy couldn’t resist letting loose a whoop of triumph. Robot said, cool and ironic, ‘You realize, Seyoura, that the mass difference between the ship and that moon is not so great that the slingshot encounter will have no effect. I calculate that in a couple of billion years the moon’s orbit will have changed enough to break up the section of ring it is presently shepherding.’

  ‘The rings will have broken up long before that anyhow. They’re not stable.’

  ‘That’s the point,’ Robot said, and laughed, the first time she’d heard him laugh. It sounded like some ancient ventilating machine, a regular creaking gasp repeated half a dozen times and then shut off. ‘So,’ he said, ‘where are we heading?’

  ‘Right now we’ve got another course correction. Using Saturn this time.’

  ‘But what’s our destination?’

  Might as well get it over with. Suzy said, ‘I’ll tell you, Robot, there’s no way we can rest easy on any of the ten worlds after this shit. So I’m going for broke here, like it or not.’

  ‘Kind of audience that would appreciate me can’t be found on any colony world, Captain.’

  ‘Quit calling me that! We aren’t headed for any colony world, anyway. After Saturn we’ve really got to jack up our velocity. We’re gonna do a momentum transfer around a—’

  Robot said, ‘Hey, now wait. Wait a moment. You think I’m crazy?’ He was sort of squirming in his crash cocoon, but couldn’t move more than a centimetre each side.

  Suzy said, ‘You should have asked, man, before you hitched your ride. Just calm down, let me fly the ship. I got us this far, didn’t I? So, hey, trust me.’

  She tried to tell him about the stuff they might find, that might make them both richer than the luckiest singleship explorer that ever lived, but he kept yelling back at her, or quoting chapter and verse from the laws against kidnap and piracy in Machine’s neutral voice, so she switched off the internal s&v and turned her attention outward. Let him work out for himself that he didn’t really have a choice.

  The rings were far behind them now, swallowed by the shadow of the planet. Bands of cloud wider than Earth’s diameter streamed below the ship. Salmon, umber, ochre, edges peeling away, mixing in complex scrolls, diminishing towards vast dim hexagonal patterns at the pole. And then the terminator swallowed them and the stars came out. Ahead, the shadow of the rings cut a narrow ellipse out of their drifts.

  Saturn’s cloud streams were still faintly visible, limned by luminescent nodes and curlicues. Far across his dark curve, a faint flickering marked the top of an electrical storm at least as big as Titan.

  Suzy snatched an hour of sleep, woke to the buzzer of the alarm. Sour furry taste in her mouth that she washed away with a mouthful of water from the tube inside her helmet while looking around at the vast panorama of the nightside of Saturn, the stars beyond. She couldn’t see her target, of course, but she knew where it was. And felt the complex contraspace coördinates beginning to surface…

  Robot was immobile inside his cradle of cables. Sleeping was Suzy’s first thought; but when she zoomed in to look at his face through the helmet’s visor she saw that the weird omega-shaped spectacles he’d put on before zipping up were filmed over. A private movie, or maybe it was a dream, externalized, turned into a movie…Whatever else might happen, having Robot aboard was going to make this a weird trip.

  The rings were edge on, a line of black so thin against the starscape that it was almost impossible to trace, rushing past as the ship shot through the three-thousand-kilometre-wide gap of the Cassini division, proximity indicators smearing across Suzy’s vision for an eyeblink, gone.

  Rising into the light of the Sun again, with added velocity borrowed from Saturn’s orbital momentum. Figures unreeling in a grid off-centre of her forward vision, countdown to reignition of the reaction motor. It’d been unreeling ever since she’d shut down the motor before the first slingshot encounter, but out of habit she’d ignored it until it started to become critical. Now she saw nothing else as figures flung themselves back to zero. The couch slapped her length; impact gel gloving her body made a fist. Robot didn’t seem to notice. Well hell, let him be.

  Ahead, she could see those cargo tugs scattered all across the sky, doppler signatures telling her that they were all receding at incredible velocity in half a dozen different directions. They had been falling a long, long way before they had encountered Saturn.

  The cops wouldn’t know where to begin chasing them down, but Suzy knew at once which one had to be piloted by Talbeck Barlstilkin. Because it was holding exactly the same course as her own ship—it was her ship now: already she had grown into every corner of it—receding out towards the point in Sol’s gravity well where a ship could safely drop into contraspace. By the time she reached that point she would be matching Barlstilkin’s delta vee but he would be long gone, three days ahead of her at least, on his way to the next target. And Suzy would follow, to the neutron star and beyond, and if she was still sucker bait she wouldn’t find out until they reached the hypervelocity star.

  PART TWO

  * * *

  Iron Stars

  1

  * * *

  It had once been an ordinary main sequence star twice as big as Earth’s Sun, hotter and bluer, stabilized at a point where pressure of radiation driven outward by the temperature of its fusion processes balanced the compressive potential energy of its own gravity. It had burned that way for perhaps five billion years. Long enough for life to have evolved on one of its planets, if it had had planets, long enough for great and glorious civilizations to have risen and fallen, or to have ruled for longer than any human dictator has ever dreamed of ruling…but nothing is for ever.

  Every second of its existence on the main sequence, the star had burnt prodigious amounts of hydrogen, fusing tonnes per second into helium and a smattering of carbon and oxygen. That was all right. It had plenty of hydrogen, enough for sixty billion years. But as hydrogen fused into heavier elements, the density at the star’s core increased: and at higher densities it was more difficult for radiation to escape. Slowly, at a rate imperceptible on any human scale, the core temperature rose, until about ten per cent of the hydrogen had fused to helium and the first critical point was reached. For now the star’s contraction had raised its core temperature to a point where less efficient burning cycles could take place: carbon to helium and neon and magnesium; oxygen to helium and silicon and sulphur; silicon to nickel. Like a metastasizing cancer, these reactions spread out from the core. The star grew bigger, inflated by radiation pressure into a red giant (vaporizing those marvellous, hypothetical civilizations and their hypothetical planet). A kind of feverish oscillation set in, cycles of contraction and expansion interspersed with unstable flares when radiation pressure grew so great that shells of unburnt hydrogen and helium were ejected from the tenuous outer atmosphere.

  This, too, could not last for ever. For all thermonuclear reactions lead inexorably to iron, and ordinarily, iron (as the architects of Dis well knew) will not burn: the energy needed to convert it to any other element is greater than the energy released by the reaction. In the outer layers of the star, the nuclear furnaces, banked with slag, grew ever dimmer. Yet, paradoxically, the core temperature rose higher than ever, heated by gravitational contraction as more and more iron accumulated and it grew ever denser. And so the second critical point was reached, when the temperature at the core reached such phenomenal values that iron nuclei spontaneously broke down into heliu
m, absorbing prodigious quantities of energy in the process.

  In an instant, the core temperature plunged by a billion degrees. It no longer radiated enough energy to overcome its own gravitational pull. Gravity had at last won over light. The star collapsed in a catastrophic cascade of X-rays as electrons and protons were crushed together to form neutrons. It was all over in a handful of days, an eye’s blink in the star’s long lifetime. All that was left was a perfect sphere twenty kilometres across, a thin crust of iron and degenerate matter covering a superfluid of bare neutrons, protons and electrons and a core of solid neutronium, the densest material in the apprehensible Universe: the corpse of a star at the bottom of an immensely steep gravity well, spinning at a tremendous rate because it still retained the angular momentum of the very much larger body it had once been.

  But even spin is not for ever.

  Three hours and ten million kilometres out, the ship’s optical systems were at last able to detect the ancient neutron star. Dorthy was watching it on the bridge, leaning forward in the middle of the huge wraparound command couch, chin resting on her doubled fists, elbows resting on knees as she stared intently into the navigation tank.

  There was little to see. The neutron star was a dim, evenly red circle like the last ember of a dying fire. From the warping of its magnetic fields through the tenuous gas shells which still surrounded it, Dorthy had calculated that it was spinning very slowly for an object of its class, once every 3240 seconds. Every so often a star drifted behind it, and then a perfectly circular flash limned the dim red disc as its gravity lensed light in every direction. That was what Dorthy was watching. No human eye had ever seen it before, for no one had ever dared fly a ship so close to such a dangerous object.

  Barlstilkin had told her that he had spent a year’s income finding the ancient neutron star. He’d had a gravity telescope built at the outer edges of the Oort Cloud, half a light year from Sol, where a billion cold comets eternally orbit and Sol’s gravity well is so flat that it is virtually nonexistent. A research team of half a dozen astronomers had been put together. (Dorthy recognized most of the names; she had studied at Fra Mauro with two of them, until fate and war and her Talent had plucked her from her budding career as research astronomer, set her down on a dry planoformed world inhabited by the Enemy.) In less than six weeks the team had pinpointed a transfer point for the hypervelocity star, a binary system of white dwarf and ancient slow-spinning neutron star which by a fortunate coincidence was one hundred and fifteen light years from Sol, and in the rough direction of Sagittarius.

  The original plan had been for a double flyby, looping first around the white dwarf, flipping back into contraspace and crossing the quarter-light-year gulf before flipping out again, diving close to the neutron star and gaining enough of its store of kinetic energy in the momentum transfer to match the hypervelocity star’s runaway proper motion. A tricky, complex manoeuvre but safer than trying to gain velocity from the neutron star alone, which would take the ship very close to the gravity well’s tidal limit. But that was what Barlstilkin now proposed to do. Take the quicker course even if it was more dangerous.

  In that respect at least, he was like his friend, Duncan Andrews. Reckless, impatient, brimming with misplaced confidence, the Universe an endless playground. Dorthy knew better. It was, in part, the message she had brought back from P’thrsn. The Galaxy was not virgin territory ripe for conquering, but a palimpsest over-scribbled with the histories of other intelligent species. Humankind was merely the latest player on that crowded stage, a cocky newcomer dazzled by the lights, unaware of the audience waiting in judgement beyond the glare. She herself had been a witness to a final act of a family drama that had taken more than a million years to play out, that had incidentally destroyed a rising civilization on Novaya Rosya and would have destroyed human civilization too, but for a great deal of luck.

  Like all Golden Dorthy had ever known, Talbeck Barlstilkin was indifferent to this kind of lesson in the dangers of hubris. He planned to live for ever, and at the same time he burned with impatience. Revenge is a dish best served cold, and he had brooded for sixty years on the real and imagined wrongs done to his family, spent half a dozen more fitting together the elements of his vengeance. But now his plans had come so close to unravelling he would take every risk necessary to keep them running.

  Dorthy was musing over that paradox and watching starlight flash around the ember of the neutron star, when Barlstilkin surprised her. She had grown so used to his presence in the ship’s cramped quarters that she didn’t realize he was there until he spoke. In the days between the encounter with Saturn and reaching the point where the Sun’s gravity field was flat enough to allow transition into contraspace, Dorthy had taken to putting on a pressure suit and drifting out from the ship on a kilometre-long tether, until it was just another point of light amongst the massed stars. It had been a welcome release from the itchy awareness of Barlstilkin’s suppressed rage, the dead mind of his bonded servant. Transit through contraspace had been an almost unbearable trial, despite the fact that her implant was blocking all but a residual activity of her Talent. One hundred and fifty days locked in a tiny ship with an animated corpse and a Golden with an urge for revenge so strong it bordered on the psychotic. Dorthy had lapsed into her old prison habits with an ease that frightened her. Reading, eating, sleeping. Mostly sleeping: after the ten years of prison even Shakespeare had lost his savour. She’d done some cold sleep, too. And now they were travelling too fast, and there was too much gas and too much radiation, for escape by spacewalking.

  The only escape was to stay inside her own head as much as possible. So when Barlstilkin spoke, Dorthy gave a little jump, and he chuckled, pleased to have startled a Talent.

  ‘There’s but two hours till transit,’ he said. ‘We should repair to our coffins soon. But before we do, something you should know.’ He reached over and spun the ball that controlled the ship’s visual cluster, bracketed the volume of starry space sternward. The green-white point of the white dwarf was off to the edge. Planet-sized iron corpse of a star too small to collapse all the way to neutrons; mere electron degeneracy able to balance gravity’s compression. ‘Computer, run back visual record thirty-five minutes,’ Barlstilkin said.

  Something glittered in the centre of the tank, fading before Dorthy could be sure she’d really seen it. Barlstilkin said, ‘False photons. Another ship just made transit.’

  ‘The Navy?’

  ‘Perhaps. Although it’s a singleship, civilian registration. It’s taking the fast route too, but we’re several days ahead of it.’ Talbeck Barlstilkin was feeling a kind of grim satisfaction: this was retroactive justification for the risk he was taking.

  Dorthy twisted to look up at him. Shadow and the dim light of the bridge conspired to mask the livid ruin of the left side of his face. He looked broodingly noble, a resurrected ninja bent on revenge according to an ancient, atavistic code of honour…

  Dorthy said, ‘It could be those friends of yours from Titan.’

  ‘I suppose that would be better than the Navy or the RUN police. But not by much.’

  ‘Well, I suppose we’ll find out when we reach the hypervelocity star.’

  Barlstilkin looked down at her. ‘You are so very calm about this, Dorthy. Detached. As if you aren’t really living through it, just watching. We could die in a couple of hours, you know. There is a distinct possibility that the ship will be torn apart by the neutron star’s gravity. We have to go very close to the Roche limit.’

  ‘I haven’t been brought all this way to end up as a hoop of disrupted molecules in orbit around an ember.’

  Barlstilkin was remotely amused. ‘The thing that is in your head tells you this?’ It was not as important as his revenge: nothing was.

  ‘I don’t know,’ Dorthy confessed, for perhaps the tenth time. ‘I’ve been living with it so long now that I can’t tell what’s me, what isn’t. I’ve been probed by half a dozen Talents, when the Navy had
me, and they couldn’t crack it either, but I’m not surprised. She was very old, very cunning.’

  ‘The neuter female. Who killed poor Duncan.’

  ‘Andrews killed her. She wanted it. But I suppose she killed him, too, in a way.’ Memory of the strange plaza was suddenly strong…the dim light of the bridge was very like the light of the red dwarf sun of P’thrsn. Rows of Alea watching her like shaggy monks, narrow faces hidden in their cowls of naked skin. The neuter female reclining like an obscene parody of Buddha, the cloud of the residual selves of her sisters, whom she had murdered and absorbed, whirling in a double lobe.

  ‘Whatever she did to me,’ Dorthy said, ‘she did for a purpose. Maybe she knew about the hypervelocity star. She had a radio telescope. Maybe she knew that the marauders were coming all along…Shit, Barlstilkin, I don’t know Parts of her were a million years old, and she was alien, so very alien. I thought I knew, then. But maybe that’s what she wanted me to believe.’

  Dorthy was shivering, suddenly. Barlstilkin laid a hand on her shoulder. It was the first time he had touched her since he had woken her, back on the ancient composite ship. He said, ‘We ought to set ourselves for the transit.’

  The ship, originally an intrasystem cargo tug which had spent half a century hauling cargo pallets from Earth to Mars and back, was a battered old workhorse with the bare minimum of living space. Barlstilkin’s renovations had left even less room. The commons was a stark volume of about a hundred cubic metres, curved in a horseshoe around the pod which housed the power system and the spine of the phase graffle. Steel mesh floor, unshaded glotubes, a scattering of functional furniture. The bonded servant was collapsing couches and fastening them down as Barlstilkin and Dorthy came down the helical stair. She didn’t pause or even look up as they went past into the crawlway down to their cabins, little asymmetrical cubicles jammed in the spaces left over between the reaction motor and the environmental recycling system and the phase graffle.