The Revelation Space Collection (367 page)

‘You call yourselves shadows. Isn’t that a bit of a giveaway?’

‘We call ourselves shadows because that is what we are, just as you are all shadows to us. It’s a statement of fact, Quaiche, not a theological standpoint.’

‘I don’t want to hear any more of it.’

It was true: he had heard enough of their heresies. They were lies, engineered to undermine his faith. Time and again he had tried to purge them from his head, but always to no avail. As long as the scrimshaw suit remained with him - as long as the thing inside the scrimshaw suit remained - he would never be able to forget those untruths. In a moment of weakness, a lapse that had been every bit as unforgivable as the one twenty years earlier that had brought them here in the first place, he had even followed up some of their heretical claims. He had delved into the Lady Morwenna’s archives, following lines of enquiry.

The shadows spoke of a theory. It meant nothing to him, yet when he searched the deep archives - records carried across centuries in the shattered and corrupted data troves of Ultra trade ships - he found something, glints of lost knowledge, teasing hints from which his mind was able to suggest a whole.

Hints of something called brane theory.

It was a model of the universe, an antique cosmological theory that had enjoyed a brief interlude of popularity seven hundred years in the past. So far as Quaiche could tell, the theory had not been discredited so much as abandoned, put aside when newer and brighter toys came along. At the time there had been no easy way of testing any of these competing theories, so they had to stand and fall on their strict aesthetic merit and the ease with which they could be tamed and manipulated with the cudgels and barbs of mathematics.

Brane theory suggested that the universe the senses spoke of was but one sliver of something vaster, one laminate layer in a stacked ply of adjacent realities. There was, Quaiche thought, something alluringly theological in that model, the idea of heavens above and hells below, with the mundane substrate of perceived reality squeezed between them. As above, so below.

But brane theory had nothing to do with heaven and hell. It had originated as a response to something called string theory, and specifically a conundrum within string theory known as the hierarchy problem.

Heresy again. But he could not stop himself from delving deeper.

String theory posited that the fundamental building blocks of matter were, at the smallest conceivable scales, simply one-dimensional loops of mass-energy. Like a guitar string the loops were able to vibrate - to
twang
- in certain discrete modes, each of which corresponded to a recognisable particle at the classical scale. Quarks, electrons, neutrinos, even photons, were all just different vibrational modes of these fundamental strings. Even gravity turned out to be a manifestation of string behaviour.

But gravity was also the problem. On the classical scale - the familiar universe of people and buildings, ships and worlds - gravity was much weaker than anyone normally gave it credit for. Yes, it held planets in their orbits around stars. Yes, it held stars in their orbits around the centre of mass of the galaxy. But compared to the other forces of nature, it was barely there at all. When the Lady Morwenna lowered one of its electromagnetic grapples to lift some chunk of metal from a delivery tractor, the magnet was resisting the entire gravitational force of Hela - everything the world could muster. If gravity had been as strong as the other forces, the Lady Morwenna would have been crushed into an atom-thick pancake, a film of collapsed metal on the perfectly smooth spherical surface of a collapsed planet. It was only gravity’s extreme weakness on the classical scale that allowed life to exist in the first place.

But string theory went on to suggest that gravity was really very strong, if only one looked closely enough. At the Planck scale, the smallest possible increment of measurement, string theory predicted that gravity ramped up to equivalence with the other forces. Indeed, at that scale reality looked rather different in other respects as well: curled up like dead woodlice were seven additional dimensions - hyperspaces accessible only on the microscopic scale of quantum interactions.

There was an aesthetic problem with this view, however. The other forces - bundled together as a single unified electroweak force - manifested themselves at a certain characteristic energy. But the strong gravity of string theory would only reveal itself at energies ten million billion times greater than for the electroweak forces. Such energies were far beyond the grasp of experimental procedure. This was the hierarchy problem, and it was considered deeply offensive. Brane theory was one attempt to resolve this glaring schism.

Brane theory - as far as Quaiche understood it - proposed that gravity was really as strong as the electroweak force, even on the classical scale. But what happened to gravity was that it leaked away before it had a chance to show its teeth. What was left - the gravity that was experienced in day-to-day life - was only a thin residue of something much stronger. Most of the force of gravity had dissipated
sideways
, into adjoining branes or dimensions. The particles that made up most of the universe were glued to a particular braneworld, a particular slice of the laminate of branes that the theory referred to as the bulk. That was why the ordinary matter of the universe only ever saw the one braneworld within which it happened to exist: it was not free to drift off into the bulk. But gravitons, the messenger particles of gravity, suffered no such constraint. They were free to drift between branes, sailing through the bulk with impunity. The best analogy Quaiche had been able to come up with was the printed words on the pages of a book, each confined for all eternity to one particular page, knowing nothing of the words printed on the next page, only a fraction of a millimetre away. And then think of book-worms, gnawing at right angles to the text.

But what of the shadows? This was where Quaiche had to fill in the details for himself. What the shadows appeared to be hinting at - the heart of the heresy - was that they were messengers or some form of communication from an adjacent braneworld. That braneworld might have been completely disconnected from our own, so that the only possible means of communication between the two was through the bulk. There was another possibility, however: the two apparently separate braneworlds might have been distant portions of a single brane, one that was folded back on itself like a hairpin. If that were the case - and the shadows had said nothing on the matter either way - then they were messengers not from another reality but merely from a distant corner of the familiar universe, unthinkably remote in both space and time. The light and energy from their region of space could only travel along the brane, unable to slip across the tiny gap between the folded surfaces. But gravity slipped effortlessly across the bulk, carrying a message from brane to brane. The stars, galaxies and clusters of galaxies in the shadow brane cast a gravitational shadow on our local universe, influencing the motions of our stars and galaxies. By the same token, the gravity caused by the matter in the local part of the brane leaked through the bulk, into the realm of the shadows.

But the shadows were clever. They had decided to communicate across the bulk using gravity as their signalling medium.

There were a thousand ways they might have done it. The specifics didn’t matter. They might have manipulated the orbits of a pair of degenerate stars to produce a ripple of gravitational waves, or learned how to make miniature black holes on demand. The only important thing was that it could be done. And - equally importantly - that someone would be able to pick up the signals on this side of the bulk.

Someone like the scuttlers, for instance.

Quaiche laughed to himself. The heresy made a repulsive kind of sense. But then what else would he have expected? Where there was the work of God, would there not also be the work of the Devil, insinuating himself into the schemes of the Creator, trying to robe the miraculous in the mundane?

‘Quaiche?’ the suit asked. ‘Are you still here?’

‘I’m still here,’ he said. ‘But I’m not listening to you. I don’t believe what you say to me.’

‘If you don’t, someone else will.’

He pointed at the scrimshaw suit, his own bony-fingered hand hovering in his peripheral vision like some detached phantasm. ‘I won’t let anyone else be poisoned by your lies.’

‘Unless they have something you want very badly,’ the scrimshaw suit said. ‘Then, of course, you might change your mind.’

His hand wavered. He felt cold suddenly. He was in the presence of evil. And it knew more about his schemes than it had any right to.

He pressed the intercom control on his couch. ‘Grelier,’ he snapped. ‘Grelier, come here this instant.
I need new blood
.’

TWENTY-SIX

Hela, 2727

The next day Rashmika got her first view of the bridge.

There was no fanfare. She was inside the caravan, in the forward observation deck of one of the two leading vehicles, having forsworn any further trips to the roof after the incident with the mirror-faced Observer.

She had been warned that they were now very close to the edge of the fissure, but for all the long kilometres of the approach there had been no change in the topography of the landscape. The caravan - longer than ever now, having picked up several more sections along the way - was winding its ponderous way through a sheer-sided ice canyon. Occasionally the moving machines scraped against the blue-veined canyon walls, which were twice as high as the tallest vehicle in the procession, dislodging tonnes of ice. It had always been hazardous for the walkers making their way to the equator on foot, but now that they had to traverse the same narrow defile as the caravan, it must have been downright terrifying. There was no room for the caravan to steer around them now, so they had to let it roll over them, making sure they were not aligned with the wheels, treads or stomping mechanical feet. If the machines didn’t get them, the falling ice-boulders probably would. Rashmika watched with a mingled sense of horror and sympathy as the parties vanished from view beneath the huge hull of the caravan. There was no way to tell if they made it out the other side, and she doubted that the caravan would stop if there was an accident.

There came a point where the canyon made a gentle curve to the right, blocking any view of the oncoming scenery for several minutes, and then suddenly there was an awful, heart-stopping absence in the landscape. She had not realised how used she had become to seeing white crags stepping into the distance. Now the ground fell away and the deep black sky dropped much lower than it had before, like a curtain whose tangled lower hem had just unfurled to its fullest extent. The sky bit hungrily into the land.

The road emerged from the canyon and ran along a ledge that skirted one wall of Ginnungagap Rift. To the left of the road, the sheer-sided canyon wall lurched higher; to the right, there was nothing at all. The road was just broad enough to accommodate the two-vehicle-wide procession, with the right-hand sides of the right-hand vehicles never more than two or three metres from the very edge. Rashmika looked back along the extended, motley train of the caravan - which was now thrillingly visible in its entirety as it had never been before - and saw wheels, treads, crawler plates, piston-driven limbs and flexing carapacial segments picking their way daintily along the edge, scuffing tonnes of ice into the abyss with each misplaced tread or impact. All along the caravan, the individual masters were steering and correcting like crazy, trying to navigate the fine line between smashing against the wall on the left and plunging over the side on the right. They couldn’t slow down because the whole point of this short cut was to make up valuable lost time. Rashmika wondered what would happen to the rest of the caravan if one of the elements got it wrong and went over the side. She had seen the inter-caravan couplings, but had no idea how strong they were. Would that one errant machine take the whole lot with it, or fall gallantly alone, leaving the others to close up the gap in the procession? Was there some nightmarish protocol for deciding such things in advance: a slackening of the couplings, perhaps?

Well, she was up front. If anywhere was safe, it had to be up at the front where the navigators had the best view of the terrain.

After several minutes during which no calamity occurred, she began to relax, and for the first time was able to pay due attention to the bridge, which had been looming ahead all the while.

The caravan was moving in a southerly direction, towards the equator, along the eastern flank of Ginnungagap Rift. The bridge was still some way south. Perhaps it was her imagination, but she thought she could see the curvature of the world as the high wall of the Rift marched into the distance. The top was jagged and irregular, but if she smoothed out those details in her mind’s eye, it appeared to follow a gentle arc, like the trajectory of a satellite. It was very difficult to judge how distant the bridge was, or how wide the Rift was at this point. Although Rashmika recalled that the Rift was forty kilometres wide at the point where the bridge spanned it, the ordinary rules of perspective simply had no application: there were no visual cues to assist her; no intermediate objects to offer a sense of diminishing scale; no attenuation of detail or colour due to atmosphere. Although the bridge and the far wall looked vast and distant, they could as easily have been five kilometres away as forty.