Xeelee: An Omnibus: Raft, Timelike Infinity, Flux, Ring (141 page)

‘Yes . . . wizened stars, faded galaxies. Depressing, isn’t it?’

She smiled. ‘Maybe. But the sky’s become an astrophysicist’s dream lab.’

‘But it can’t have been much of a dream for anyone left alive here, in the Solar System, when those novae and supernovae started going off. The sleet of hard radiation and massive particles must have been unrelenting, for a million years . . .’

‘Yes. A hard rain indeed. That will have sterilized the whole damn place—’

‘—if there had been anyone left alive here by then. Which we’ve yet to find evidence of. Well, we’re still following up our four leads - the maser radiation coming out of the Sun, the
very
strange gravity waves coming from Sagittarius, the artifact in the ice, here on Callisto, and that weak beacon in transPlutonian space . . . But we’re no further forward understanding any of it.’

‘I can see the forest,’ Spinner murmured, her faceplate upturned.

Louise studied the lifedome more carefully, enhanced the image with artificial colours - and there, indeed, she could see a thin layer of Earth green at the leading edge of the lifedome, the layer of living things stained dark by the aged sunlight.

That pet forest, she thought suddenly, might be the only
green
left, anywhere in the Universe.

Absurdly, she felt her throat tightening; she found it difficult to pull her gaze away from that drifting particle of
home.

There was a hand on her arm, its weight barely registering through the numbing, stiff fabric of the suit. Spinner smiled. ‘I know how you feel.’

Louise peered through the faceplate at this odd girl-woman, with her glinting spectacles and her round, childish face.

After Spinner’s father had wrecked the Interface - and with it, any chance of getting home again - Louise had offered Spinner and her people AS-treatment. And, looking at Spinner now, fifty years later, it was hard to remember that this was no longer a child, but a sixty-five-year-old woman.

‘I
doubt
you know how I feel,’ she said coldly. ‘I doubt it very much.’

Spinner studied her for a few moments, her painted face expressionless behind her plate.

They climbed back into the pod.

The little ship rose to a height of a mile, then levelled off and coasted parallel to the surface. Louise looked back. Their landing jets had blown a wide, shallow crater in the ice; it marred a plain which stretched, seamless and featureless, to the close horizon.

Louise sat in her seat; surrounded by the disconcertingly transparent hull, she felt - as always, in these pods - as if she were suspended in space. Below them the Callisto plain was a geometrical abstraction; above them,
Northern
climbed patiently past the deep, gleaming rings of Jupiter, a spark against those smooth arcs.

The main activity on Callisto was centred around Morrow’s excavation site on the far side of the moon, the Jupiter-facing side. The purpose of this jaunt was to have a general scout, and to give Spinner-of-Rope some more experience of working outside the ship, the
feel
of standing on a planet surface . . . Even, Louise thought, a surface so featureless, and with a sky so bare, that the moon had become almost an abstract representation of a planet.

Still, Louise knew it did
her
good to get away from the ship that had been her home, and prison, for so many centuries - and which, barring a miracle, was going to have to sustain her and her people for the rest of her life. Callisto was - had been - Jupiter’s eighth moon, one of the four big Galilean satellites. At the time of
Northern
’s launch, Callisto had been a ball of water ice and rock, heavily cratered. Debris had been sprayed across the mysterious surface from the bright cores of the impact craters; from space, Callisto had looked like a sphere of glass peppered by gunshots. One basin - called Valhalla - had been four hundred miles across, an immense amphitheatre surrounded by concentric terrace-like walls.

Louise remembered how human cities, feeding on Callisto’s ancient water, had glinted in the shadows of Valhalla’s walls, shining like multicoloured jewels.

Well, the craters had gone now - as had Valhalla, and all the cities. Gone without trace, it seemed. Callisto had been wiped smooth, unblemished save for her own footsteps.

During, or after, the depopulation, Callisto had been caused to
melt
. And, when the moon froze once more, something had been trapped in the ice . . .

The pod skimmed around the smooth limb of the moon. They were heading over the moon’s north pole, and soon, Louise realized, they would be passing over the sharp terminator and into daylight.

. . . Or what passed for daylight, in these straitened times, she thought. Beside her, Spinner fitted her faceplate over her head, leaving it open below her mouth. She peered around, through the flimsy walls of the pod. From the absent, unfocused expression in her eyes, Louise could tell she was using the plate’s enhancement and magnification features.

‘I can see moons,’ Spinner said. ‘A sky full of moons.’

‘Nice for you,’ Louise said dryly. ‘There should be eight - there used to be eight beyond Callisto. Small, irregular: probably captured asteroids. The outer four of them were retrograde, moving backwards compared to the planet’s own rotation.’

‘I’m surprised any moons survived the destruction of the planet.’

Louise shrugged. ‘The nearest of the outer moons was a hundred and fifty Jovian radii from the primary, before the planet imploded . . . even Callisto survived, remember, and that was a mere twenty-six radii out.’ The orbits of the surviving moons had been disturbed by the Jovian event, of course; the implosion had sent them scattering with a shock of gravity waves, and now they swooped around their shattered parent along orbits of high eccentricity, like birds disturbed by earth tremors.

Within the orbit of Callisto, nothing had survived.

Now, as the pod passed over the pole, the Jovian ring system unfolded like a huge floor before Louise, infinite-flat and streaked with shadows.

This new ring system, the debris of worlds, lay in what had been Jupiter’s equatorial plane - the plane once occupied by the vanished moons. Callisto still lay in the equatorial plane, patiently circling the site of the giant planet just outside the ring system, so that the disc of ring material - if it had stretched out so far - would have bisected Callisto neatly.

The ring system didn’t terminate at a sharp inner boundary, like Saturn’s. Instead the creamy, smoothed-out material stretched inwards - this system was actually more a disc than a ring system, Louise realized slowly. As her eyes tracked in towards the centre the system’s texture slowly changed - becoming more rough, Louise saw, with knots of high density locked into the churning surface, orbiting through tight circles, swirling visibly.

The whole assemblage was stained crimson by scattered sunlight.

The rings were almost featureless -
bland
, without the complex colours and braids which characterized Saturn’s system. Louise sighed. The gravitational interaction of moons had provided Saturn’s rings with their fantastic structure. The trouble was that Jupiter’s remaining moons simply weren’t up to the job of shepherding the rings. For poor, dead Jupiter, only a single dark streak marked the orbital resonance of Callisto itself.

Now, the centre of the ring-disc rose above Callisto’s sharp horizon. Louise could clearly see inhomogeneities churning around the geometric centre of the disc, twisting through their crowded, tortured orbits. But the disc centre itself was unspectacular - just a brighter patch, spinning with the rest of the disc. It was somehow frustrating, as if there were something missing.

Spinner sounded disappointed. ‘I can’t see anything in the middle. Where the planet used to be.’

Louise grinned. ‘You’d hardly expect to. A black hole with Jupiter’s mass would have a diameter of just twenty feet or so . . .’

‘There’s plenty to see in higher frequencies,’ Mark cut in. ‘The X-ray, and higher . . .

‘Towards the heart of the system we have a true accretion disc,’ he went on, ‘with matter being heated tremendously before falling into the black hole itself. It’s small, but there’s a lot of structure there, if you look at it in the right bands.’

Spinner, with apparent eagerness, adjusted her plate over her face, and Mark told her how to fix the settings. Soon, Spinner’s eyes assumed that unfocused look again as they adjusted to the enhanced imagery.

Louise left her own visor in her lap; the black hole, and its huge, milky ring, depressed her enough in visible light.

Jupiter’s new ring system, with its bland paleness, and the jostling, crowding swirl at the centre, was far from beautiful, on any wavelength. It was too obviously a place of wreckage, of
destruction -
a destruction which was visibly continuing, as the black hole gnawed at its accretion disc. And, to Louise’s engineer’s eye, with its empty centre the system had something of an unfinished, provisional look. There was no
soul
to this system, she thought, no balance to the scale of the rings: by comparison, Saturn’s rings had been an adornment, a necklace of ice and rock around the throat of an already beautiful world.

Spinner turned to her, her bespectacled eyes masked by the faceplate. ‘The whole thing’s like a whirlpool,’ she said.

Louise shrugged. ‘I suppose so. A whirlpool surrounding a hole in spacetime.’

‘A whirlpool of gas—’

—
gas, and rock and water ice: bits of smashed-up worlds—

Louise started to tell Spinner-of-Rope about the vanished moons of Jupiter. She remembered Io with its volcano mouths and their hundred-mile-high vents, its sulphur-stained surface and its surrounding torus of volcano-fed plasma; she remembered Io’s mineral mines, nestling in the shadow of the huge volcano Babbar Patera. She told Spinner of Ganymede: larger than Mercury, heavily cratered and geologically rich - the most stable and heavily populated of all the Jovian moons. And Europa, a ball of ice, with a bright smooth surface - constantly renewed by melting and tectonic stress - covering a liquid layer beneath. Europa had been a bright precursor of this smoothed-over corpse of Callisto, perhaps.

Worlds
, all populated - all gone.

Louise hoped fervently that there had been time to evacuate the moons before the final disaster. If not, then - drifting through Jovian orbit among the fragments of rock and ice which comprised those rings - there would be bits of humanity: shards of shattered homes, children’s toys, corpses.

Spinner pushed up her faceplate and rubbed her eyes. ‘I’d have liked to have seen Jupiter, I think, with its moons and all those cities . . . Perhaps Jupiter could have been saved. After all, the implosion must have taken thousands of years, you told me.’

Louise bit back a sarcastic reply. ‘Yes. But picking black holes out of the heart of a gas giant was evidently a bit too difficult, even for the humans of many millennia beyond my time.’

Jupiter had been wrecked by the actions of the Friends of Wigner.

The Friends were human rebels from a Qax-occupied future, who had fled back in time through Michael Poole’s time-tunnel wormhole.

The Friends had had in mind some grand, impossible scheme to alter history. Their plan had involved firing asteroid-mass black holes into Jupiter.

The Friends’ project had been interrupted by the arrival of Qax warships through Poole’s wormhole - but not before the Friends had succeeded in spearing the giant planet with several of their tiny singularities.

The pinprick singularities had looped through the thick Jovian atmosphere like deadly insects, trailing threads of plasma. When the holes met, they had whirled around each other before coalescing, their event horizons collapsing into each other in Planck timescales.

The vibration of merging event horizons had emitted vicious pulses of gravity waves. Founts of thick, chemically complex atmosphere had been hurled out of the planet, bizarre volcanoes on a world of gas.

The Friends’ ambitions had been far-reaching. Before the final implosion they’d meant to
sculpt
the huge planet with these directed gravity-wave pulses, produced by the complex interactions of their singularity bullets.

Louise now stared morosely at the bland, displeasing disc of glowing rubble. Well, the Friends had certainly succeeded in part of their project - the reduction of Jupiter. Quite a monument to such ambition, after five million years, Louise thought: a collapsed Jovian, and a string of crushed human worlds.

And all for what? A black hole of the wrong size . . .

‘It’s getting brighter over there,’ Spinner said, pointing.

Louise looked right, across Callisto. A dull, flat crimson light was spreading across the ice. The glow cast long, disproportionate shadows from the low irregularities in Callisto’s smooth surface, turning the ice plain into a complex landscape of ruby-sparkling promontories and blood-red pools of shadow.

At the horizon, smoky tendrils of crimson gas were rising across the sky.

‘Sunrise on Callisto,’ Louise said sourly. ‘Come on; let’s land. We don’t want to miss the full beauty of the Solar System’s one remaining wonder, do we?’

On the surface of Callisto, standing beside Louise in her environment suit, Spinner held up her arms, framing the Sun with her outspread hands; standing there on the light-stained ice floor, with the swollen globe reflected, distorted, in her faceplate, Spinner-of-Rope looked more than ever like a child.

Sol, looming over the horizon, was a wall of blood-red smoke. It was transparent enough to see through to the distant stars for perhaps a quarter of the disc’s radius - in fact, the material was so thin that Louise could make out the steadily deepening colour of the thicker layers towards the core.

The Sun didn’t even
look
like a star any more, she thought tiredly. A star was supposed to be hard, bright, hot; you weren’t supposed to be able to see
through
it.