Xeelee: An Omnibus: Raft, Timelike Infinity, Flux, Ring (126 page)

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

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

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

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

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

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

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

Hard to tell, and harder to care.

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

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

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

The divergence, of theory from observation, was
immense -
and increased towards the centre of the Sun.

‘Kevan, it’s
way
too hot out here.’

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

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

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

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

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

Almost.

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

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

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

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

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

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

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

‘Kevan. Am I still falling?’

‘Nominal. I hate that word.’

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

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

She smiled.

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

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

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

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

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

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

There was a motion behind him; he turned.

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

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

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

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

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

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

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

Dark matter could age a star.

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

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

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

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

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

‘Hmm?’

‘Tell me.’

‘Go on, Kevan.’

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

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

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

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