Xeelee: An Omnibus: Raft, Timelike Infinity, Flux, Ring (145 page)

She thought,
Lethe. What now? Am I going crazy?

But, strangely, the voice - the sense of some invisible presence, here in the cage with her - was somehow
comforting.

Spinner held her right hand over the waldo. She pressed her gloved finger to the yellow light.

A subtle change in the light, around her. There was no noise, no sense of motion.

She glanced down, through the bars of her cage.

The ice was gone.
Callisto had vanished.

She twisted in her seat, the straps chafing against her chest, and peered out of her cage. The rings of Jupiter and the Sun’s swollen form covered the sky - unperturbed by the disappearance of a mere moon. She couldn’t see the
Northern.

She spotted a ball of ice, small enough to cover with her fist, off to her right, below the nightfighter.

Could that be Callisto? If so, she’d travelled thousands of miles from the moon, in less than a heartbeat - and felt nothing.

She looked behind her.

The Xeelee nightfighter had
spread
its sycamore-seed wings. From within their hundred-yard shells, sheets of night-darkness -
hundreds of miles long
- curled across space behind her, occluding the stars.

At her touch, the ancient Xeelee craft had come to life.

She screamed and buried her faceplate in her gloves.

Lieserl soared out from the core, out through the shell of fusing hydrogen, and inspected her maser convection loops. She sensed the distorted echoes of her last set of messages, as they had survived their cycles through the coherence paths of the convection loops.

She adjusted the information content of her maser links, and initiated new messages. She added in the latest information she’d gleaned, and restated - in as strong and simple a language as she could muster - her warnings about the likely future evolution of the Sun.

When she was done, she felt something within her relax. Once more she’d scratched this itch to communicate; once more she’d assuaged her absurd, ancient feelings of guilt . . .

But it was only after she’d sent her communication that she studied, properly, the cycled remnants of her last signals.

She allowed the maser bursts to play over her again. The messages had
changed -
and this time it wasn’t simple degradation. How was this possible? Some unknown physical process at the surface of the red giant, perhaps? Or - she speculated, her excitement growing as she began to see traces of structure within the changes - or was there someone
outside:
someone still alive, and recognizably human - and trying to talk to her?

Feverishly she devoured the thin information stream contained in the maser bursts.

Fifty thousand miles from Callisto, pods from the
Northern
hung in a rough sphere. At the centre of the sphere, the magnificent wings of the Xeelee ship remained unfurled, darkly shimmering - almost alive.

Spinner sat with Louise within the safe, enclosing glass walls of a pod. Louise, with a touch on the little control console before her, guided the pod around the Xeelee nightfighter; neighbouring pods slid across space, bubbles of light and warmth. The wings were immense sculptures in space, black on black. Spinner could hear Mark whispering in Louise’s ear, and numbers and schematics rolled across a data slate on Louise’s lap.

Spinner’s faceplate dangled at her back, and she relished the feel of fresh air against her face. It was
wonderful
simply not to breathe in her own stale exhalations.

She’d dug her father’s arrow-head out of her suit so that it dangled at her chest; she fingered it, rubbing her hands compulsively over its smooth lines.

Louise glanced at Spinner. ‘Are you all right now?’ She sounded apologetic. ‘Mark got to you as quickly as he could. And—’

Spinner-of-Rope nodded, curtly. ‘I wasn’t hurt.’

‘No.’ Louise glanced down at her slate again; her attention was clearly on the data streaming in about the activated nightfighter. She murmured, ‘No, you did fine.’

‘Yeah,’ Spinner grunted. ‘Well, I hope it was worth it.’

Louise looked up from her slate. ‘It
was
. Believe me, Spinner; even if it might be hard for you to see how. The very fact that you weren’t harmed, physically, by that little jaunt has told us volumes.’

Now Mark’s voice sounded in the air, ‘You travelled tens of thousands of miles in a fraction of a second, Spinner. You should have been
creamed
against the bars of that cage. Instead, something protected you . . .’

Louise looked at Spinner. ‘He has a way of putting things, doesn’t he?’

They laughed together. Spinner felt a little of the numbness chip away from her.

‘Mark’s right,’ Louise said. ‘Thanks to you, we’re learning at a fantastic rate about the nightfighter. We know we can use it without killing ourselves, for a start . . . And, Spinner, understanding is the key to turning
anything
from a threat into an opportunity.’

Louise took the pod on a wide arc around the unfurled wings of the Xeelee craft. The wings were like a star-free hole cut out of space, beneath Spinner-of-Rope; they retained the general sycamore-seed shape of the construction-material framework, but were vastly extended. Spinner could see ‘bots toiling patiently across the wings’ surface.

‘This far out, the mass-energy of the wing system is actually attracting the pod, gravitationally,’ Louise murmured. ‘The wings have the mass equivalent of a small asteroid . . . I can see from my slate that the pod’s systems are having to correct for the wings’ perturbation.

‘Let’s go in a little way.’

She took the pod on a low, sweeping curve over the lip of one wing and down towards its surface. The wing, a hundred miles across, was spread out beneath Spinner like the skin of some dark world; the little pod skimmed steadily over the black landscape.

Louise kept talking. ‘The wing is
thin
- as far as we can tell its thickness is just a Planck length, the shortest distance possible. It has an extremely high surface tension - or, equivalently, a high surface energy density - so high, in fact, that its gravitational field is inherently non-Newtonian; it’s actually
relativistic
. . . Is this making any sense to you, Spinner?’

Spinner said nothing.

Louise said, ‘Look: from a long way away, the pod was attracted to the wings, just as if they were composed of normal matter.
But they’re not
. And, this close, I can detect the difference.’

She drew the pod to a stop, and allowed it to descend, slowly, towards the wing surface.

Spinner, gazing down, couldn’t tell how far away the night-black, featureless floor was. Was Louise intending to land there?

The pod’s descent slowed.

Louise, working her control console, caused the pod’s small vernier rockets to squirt, once, twice, sending them down towards the wing surface once more. But again the pod slowed; it gradually drifted to a halt, then, slowly, began to rise, as if rebounding.

Louise’s face was alive with excitement. ‘Spinner, could you feel that? Do you see what’s happening? This close, the wing surface is actually gravitationally
repulsive
. It’s pushing us away!’

Spinner eyed her. ‘I know you, Louise. You’ve already figured out how a discontinuity drive would work. You were
expecting
this antigravity stunt, weren’t you?’

Louise smiled and waved a hand at the Xeelee craft. ‘Well, okay. Maybe I made a few educated guesses. This ship isn’t magic. Not even this antigravity effect. It’s all just an exercise in high physics. Of course we couldn’t
build
one of these.’ Her eyes looked remote. ‘Not yet, anyway . . .’

‘Tell me how it works, Louise.’

At extremes of temperature and pressure, spacetime became highly symmetrical (Louise told Spinner). The fundamental forces of physics became unified into a single superforce.

When conditions became less intense the symmetries were broken. The forces of physics - gravity, nuclear, electromagnetic - froze out of the superforce.

‘Now,’ Louise said, ‘think of ice freezing out of water. Think back to what we saw on Callisto - all those flaws inside the ice, remember? The freezing of water doesn’t happen in an even, symmetrical way. There are usually
defects -
discontinuities in the ice.

‘And in just the same way, when physical forces freeze out of the unified state, there can be defects - but now, these are defects in spacetime itself.’

Space was three-dimensional. Three types of stable defects were possible: in zero, one or two dimensions. The defects were points -
monopoles -
or lines -
cosmic strings -
or planes -
domain walls.

The defects were genuine flaws in spacetime. Within the defects were sheets - or points, or lines - of
false vacuum:
places where the conditions of the high-density, symmetrical, unified state still held - like sheets of liquid water trapped within ice.

‘These things can form naturally,’ Louise said. ‘In fact, possibly many of them did, as the Universe expanded out of the Big Bang. And maybe,’ she went on slowly, ‘the defects can be manufactured artificially, too.’

Spinner stared out of the pod at the nightfighter. ‘Are you saying—’

‘I’m saying that the Xeelee can create, and control, spacetime defects. We think that the “wings” of this nightfighter are defects - domain walls, bounded about by loops of cosmic string.

‘Spinner-of-Rope, the Xeelee use sheets of antigravity to drive their spacecraft . . .’

The domain walls were inherently unstable; left to themselves they would decay away in bursts of gravitational radiation, and would attempt to propagate away at speeds close to that of light. The Xeelee nightfighter must actually be stabilizing the flaws, actively, to prevent this happening, and then destabilizing the flaws to gain propulsion.

Louise believed the Xeelee’s control of the domain-wall antigravity effect must be behind the ship’s ability to shield the pilot cage from acceleration effects.

‘All this sounds impossible,’ Spinner said.

‘There’s no such word,’ Louise said aggressively. ‘Your trip was a real achievement. ’ Louise, clearly excited by the Xeelee’s engineering prowess, sounded as alive and full of enthusiasm as Spinner had ever heard her. ‘You gave us the first big break we’ve made in understanding how this nightfighter operates - and, more significantly, how we can use it without destroying ourselves.’

Spinner frowned. ‘And is that so important?’

Louise looked at her seriously. ‘Spinner, I need to talk this out properly with you. But I suspect how well we use this nightfighter is going to determine whether we - the human species - survive, or perish here with our Sun.’

Spinner gazed out at the Xeelee craft, at the scores of drone ‘bots which clambered busily across the face of its wings.

Perhaps Louise was right; perhaps understanding how something worked
did
make it genuinely less threatening. The Xeelee nightfighter wasn’t a monster. It was a tool - a resource, for humans to exploit.

‘All right,’ she said. ‘What next?’

Louise grinned. ‘Next, I think it’s time to figure out how to take this nightfighter on a little test jaunt around the Solar System. I’d like to see what in Lethe happened here. And,’ she said, her face hardening, ‘I want to know what’s happening to our Sun . . .’

M
ilpitas put down his pen.

Annoyingly, it drifted away from the surface of his desk and up into the air, cart-wheeling slowly; Milpitas swiftly scooped up the offending item and swept it into a drawer, where it could drift about to its little insensate heart’s content.

He climbed stiffly from his chair and made his slow way from the office.

Fine white ropes had been strung out along the Temple’s warren of corridors. By judiciously sliding one’s closed fists along the rope, one could quite easily maintain the illusion - for oneself and others - of walking, as normal. He passed another Planner, a junior woman with her tall, shaven dome of a scalp quite gracefully formed. Her legs were hidden by a long robe, so that - at first glance anyway - it could have been that she
was
walking. Milpitas smiled at the girl, and she nodded gravely to him as they passed.

Excellent
, he thought. That was the way to deal with this ghastly, offensive situation of zero-gee, of course: by not accepting its reality, by allowing no intrusion into the normal course of things - into the usual, smooth running of their minds. By such means they could survive until gravity was restored. He moved through the corridors of his Temple, past Planner offices which had been hastily adapted to serve as dormitories and food stores. Beyond the closed doors he heard the slow, subdued murmur of the voices of his people, and beyond the Temple walls there continued the steady, sad wailing of the klaxon.

He worked his way out from the bowels of the building, out towards the glistening skin of the Temple. He had conducted an inspection tour like this every shift since the start of the emergency. His assistants formed a complex web of intelligence throughout the Temple, of course, and reports were ready for him whenever he requested them. Some contact had even been maintained with the other Temples, thanks to carefully selected runners. But, despite all that data, Milpitas still found there was no substitute for getting out of his office and
seeing
for himself what was going on.

And, he flattered himself to think, perhaps it comforted the people - the lost children he’d gathered here into his protection, in the midst of this, their greatest crisis - to be aware that he, Milpitas, their Planner, was among them.

But, he thought, what if gravity were never returned?

He pulled at his chin, his fingernails lingering on the network of AS scars they found there.