‘You can’t risk it. Pull up and out. We can come back again on the next pass, three hours from now.’
He had seen accretion discs, the swirls of matter around stellar-mass black holes and neutron stars, and what he saw near the storm’s focus looked very similar: a spiralling concentration of cloud, tortured into rainbow colours as strange, transient chemistries came into play. They were so deep in the transition zone here that even tiny pressure changes were enough to condense the air into its fluid state. Lightning cartwheeled across the focus, driven by static differentials in the moving air masses. Merlin checked the range: close now, less than two hundred kilometres away.
And something was wrong.
Pauraque’s ship was sinking too far, drifting too close to the heart of the storm. They were above it now, but their rate of descent would bring them close to the focus by the time it arrived.
‘Force and wisdom; I told you to pull up, not go deeper!’
‘We have a problem. Can’t reshape the hull on our remaining nodes. No aerodynamic control.’ Gallinule’s voice was calm, but Merlin knew his brother was terrified.
‘Vector your thrust.’
‘Hell’s teeth, what do you think I’m trying to do?’
No good. He watched the violet spikes of the other ship’s thrusters stab in different directions, but there was nothing Gallinule could do to bring them out of their terminal descent. Merlin thought of the mods Gallinule had recommended. Unless he had added some hidden improvements, the other ship would implode in ten or fifteen seconds. There would be no surviving that.
‘Listen to me,’ Merlin said. ‘You have to equalise pressure with the outside, or that hull’s going to implode.’
‘We’ll lose the ship that way.’
‘Don’t argue, just do it! You have no more than ten seconds to save yourselves!’
He closed his eyes and hoped they were both suited. Or perhaps it would be better if they were not. To die by hull implosion would be swift, after all. The inrushing walls would move faster than any human nerve impulses.
On the magnified view of the other ship he saw a row of intakes flicker open along the dorsal line. Soup-thick atmosphere would have slammed in like an iron fist. Maybe their suits were good enough to withstand that shock.
He hoped so.
The thrust flames died out. Running lights and fluorescent markings winked out. A moment later he watched the other ship come apart like something fashioned from gossamer. Debris lingered for an instant before being crushed towards invisibility.
And two bulbously suited human figures fell through the air, drifting apart as they were caught in the torpid currents that ran through the transition zone. For a moment the suits were androform, but then their carapaces flowed liquidly towards smooth egg-shapes, held rigid by the same principle that still protected Merlin’s ship. They were alive - he was sure of that - but they were still sinking, still heavier than the air they displaced. The one that was now falling fastest would pass the storm at what he judged to be a safe distance. The other would fall right through the storm’s eye.
He thought of the focus of the storm: a seething eye of flickering gamma rays, horrific gravitational stress and intense pressure eddies. They had not seen it yet, but he could be sure that was what it would be like. A black hole, even a small one, was no place to be near.
‘Final warning,’ Tyrant said, bypassing all his overrides. ‘Pressure now at maximum safe limit. Any further increase in—’
He made his decision.
Slammed Tyrant screaming towards the survivor who was headed towards the eye. It would be close - hellishly so. Even the extra margins he had built into this ship’s hull would be pushed perilously close to the limit. On the cabin window, cross-hairs locked around the first falling egg. Range: eleven kilometres and closing. He computed an approach vector and saw that it would be even closer than he had feared. They would be arcing straight towards the eye by the time he had the egg aboard. Seven kilometres. There would not be time to bring the egg aboard properly. The best he could do would be to open a cavity in the hull and enclose it. Frantically he told Tyrant what he needed; by the time he was done, range was down to three kilometres.
He felt faint, phantom deceleration as Tyrant matched trajectories with the egg and brought itself in for the rendezvous. The egg left a trail of bubbles behind it as it dropped, evidence of the transition to ocean. Somewhere on Tyrant’s skin, a cavity puckered open, precisely shaped to accept the egg. They tore through rushing curtains of cloud. In a few moments he would be near enough to see the eye, he knew. One kilometre . . . six hundred metres. Three hundred.
The faintest of thumps as the egg was captured. Membranes of hull locked over the prize and resealed. Whoever he had saved was as safe now as Merlin.
Which was really saying very little.
‘Instigate immediate pull-up. Hull collapse imminent. Severe pressure transition imminent.’
He was through the eye now, perhaps only two or three kilometres from the sucking point of the black hole. He had expected to see the clouds drawn into a malignant little knot, with a flickering glint of intense light at the heart of the whirlpool, but there was nothing, just clear skies. There was a local gravitational distortion, but it was nowhere near as severe as he had expected. Merlin glanced at the radiation alarms, but they were not showing anything unusual.
No hint of gamma radiation.
He wanted time to think, wanted to work out how he could be this close to a black hole and feel no radiation, but what was coming up below instantly demanded his attention. There was the other egg, tumbling below, wobbling as if in a mirage. Pressure was distorting it, readying to crush it. And down below, slumbering under the transition zone, was the true hydrogen sea. In a few seconds the other egg would be completely immersed in that unimaginably dense blackness and it would all be over. For a moment he considered swooping in low; trying to snatch the egg before it hit. He ran the numbers and saw the chilling truth.
He would have to enter the sea as well.
Merlin gave Tyrant its orders and closed his eyes. Even in the cushioning embrace of his suit, the hairpin turn as the ship skimmed the ocean would still not be comfortable. It would probably push him below consciousness. Which, he thought, might turn out to be the final mercy.
The sea’s hazy surface came up like a black fog.
Thought faded for an instant, then returned fuzzily; and now through the windows he saw veils of cloud towards which he was climbing. The feeling of having survived was godlike. Yet something was screaming. The ship, he realised. It had sloughed millimetres of hull to stay intact. He prayed that the damage would not prevent him from getting home.
‘The second egg . . .’ Merlin said. ‘Did we get it?’
Tyrant was clever enough - just - to know what he meant. ‘Both eggs recovered.’
‘Good. Show me . . .’
Proctors carried the first egg into the cabin, fiddling with it until they persuaded it to revert to androform shape. When the facial region became transparent he saw that it was Gallinule that this egg had saved, although his brother was clearly unconscious. Not dead though: he could tell that from the egg’s luminous readouts. He felt a moment of pure, unadulterated bliss. He had saved Gallinule, but not selfishly. He had not known which of the two eggs had been falling towards the eye. In fact, he did not even know that this was that egg. Had he plucked his brother from the sea, instants before the ocean would have crushed him?
But then he saw the other egg. The proctors, stupid to the end, had seen fit to bring it into the cabin. They carried it like a trophy, as if it were something he would be overjoyed to see. But it was barely larger than a space helmet.
PART FOUR
‘I think I know what killed her,’ Sayaca said.
The three of them had agreed to meet within the Palace of Eternal Dusk. Sayaca had arranged a demonstration, casting into the sky vast projected shapes, which she orchestrated with deft gestures
.
‘It wasn’t a black hole, was it?’ Gallinule said.
‘No.’ She took his hand in both of hers, comforting him as they dug through the difficult memory of Pauraque’s death. It had happened months ago, but the pain of it was still acute for Gallinule. Merlin watched from one side, lingeringly resentful at the tenderness Sayaca showed his brother. ‘I think it was something a lot stranger than a black hole. Shall I show you?’
A double helix writhed in the sky, luminous and serpentlike against Plenitude’s perpetual pink twilight.
Releasing Gallinule’s hand, Sayaca lifted a finger and the DNA coil swelled to godlike size, until the individual base pairs were themselves too large to discern as anything other than blurred assemblages of atoms, huger than mountains. But atoms were only the beginning of the descent into the world of the vanishingly small. Atoms were assembled from even tinier components: electrons, protons and neutrons, bound together by the electroweak and -strong forces. But even those fundamental particles held deeper layers of structure. All matter in the universe was woven from quarks or leptons; all force mediated by bosons.
Even that was not the end.
In the deepest of deep symmetries, the fermions - the quarks and leptons - and the bosons - the messengers of force - blurred into one kind of entity. Particle was no longer the right word for it. What everything in the universe seemed to boil down to, at the very fundamental level, was a series of loops vibrating at different frequencies, embedded in a multidimensional space.
What, Sayaca said, scientists had once termed superstrings.
It was elegant beyond words, and it explained seemingly everything. But the trouble with superstring theory, Sayaca added, was that it was extraordinarily difficult to test. It was likely that the theory had been reinvented and discarded dozens or hundreds of times in human history, during each brief phase of enlightenment. Undoubtedly the Waymakers must have come to some final wisdom as to the ultimate nature of reality . . . but if they had, they had not left that verdict in any form now remembered. So from Sayaca’s viewpoint, superstring theory was at least as viable as any other model for unifying the fundamental particles and forces.
‘But I don’t see how any of this helps us understand Pauraque’s storm,’ Merlin said.
‘Wait,’ said Sayaca’s semblance. ‘I haven’t finished. There’s more than one type of superstring theory, understand? And some of those theories make a special prediction about the existence of something called shadow matter. It’s not the same thing as antimatter. Shadow matter’s like normal matter in every respect, except it’s invisible and insubstantial. Objects made of normal and shadow matter just slip through each other like ghosts. There’s only one way in which they sense each other.’
‘Gravity,’ Merlin said.
‘Yes. As far as gravity’s concerned, there’s nothing to distinguish them.’
‘So what are you saying, that there could be whole universes made of shadow matter coexisting with our own?’
‘Exactly that.’ She went on to tell them there was every reason to suppose that the shadow universe was just as complex as the normal one, with exactly analogous particle types, atoms and chemistry. There would be shadow galaxies, shadow stars and shadow worlds - perhaps even shadow life.
Merlin absorbed that. ‘Why haven’t we encountered anything like shadow matter before?’
‘There must be strong segregation between the two types across the plane of the galaxy. For one reason or another, that segregation has broken down around Bright Boy. There seems to be about half a solar mass of shadow matter gravitationally bound to this system - most of it sitting in Bright Boy’s core.’
Merlin tightened his grip on the balustrade. ‘Tell me this answers all our riddles, Sayaca.’
Sayaca told them the rest, reminding Merlin how they had probed Cinder’s interior via sound waves, each sonic pulse generated by the impact of an in-falling meteorite; the sound waves tracked as they swept through Cinder, gathered by a network of listening posts sprinkled across the surface. It was these seismic images that had first elucidated the fine structure of the Digger tunnels. But - unwittingly - Sayaca had learned much more than that.
‘We measured Cinder’s mass twice. The first time was when we put our own mapping satellites into orbit. That gave us one figure. The seismic data should have given us a second estimate that agreed to within a few per cent. But the seismic data said there was only two-thirds as much mass as there should have been, compared with the gravitational mass estimate.’ Sayaca’s semblance paused, perhaps giving the two of them time to make the connection themselves. When neither spoke, she permitted herself to continue. ‘If there’s a large chunk of shadow matter inside Cinder, it explains everything. The seismic waves only travel through normal matter, so they don’t see one-third of Cinder’s composition at all. But the gravitational signature of normal and shadow matter is identical. Our satellites felt the pull of the normal and shadow matter, just as we did when we were walking around inside Cinder.’
‘All right,’ he said. ‘Tell me about Bright Boy too.’
‘It makes just as much sense. Most of the shadow matter in this system must be inside the star. Half a solar mass would be enough for Bright Boy’s shadow counterpart to become a star in its own right - burning its own shadow hydrogen to shadow helium, giving off shadow photons and shadow neutrinos, none of which we can see. Except just like Bright Boy it would be an astrophysical anomaly - too bright and small to make any kind of sense, because its structure is being affected by the presence of an equal amount of normal matter from our universe. Both stars end up with hotter cores, since the nuclear reactions have to work harder to hold up the weight of overlying stellar atmosphere.’
Sayaca thought that the two halves of Bright Boy - the normal and shadow-matter suns - had once been spatially separated, so that they formed the two stars of a close binary system. That, she said, would have been something so strange that no passing culture could have missed it, for the visible counterpart of Bright Boy would have appeared locked in orbital embrace with an invisible partner, signalling its oddity across half the galaxy. Over the ensuing billions of years, the two stars had whirled closer and closer together, their orbital motions damped by tidal dissipation, until they had merged and settled into the same spatial volume. Whoever comes after us, Merlin thought, we won’t be the last to study this cosmic mystery.
‘Then tell me about Pauraque’s storm,’ he said, flinching at the memory of her crushed survival egg.
Gallinule nodded. ‘Go on. I want to know what killed her.’
Sayaca spoke now with less ease. ‘It must be another chunk of shadow matter - about the mass of a large moon, squashed into a volume no more than a few tens of kilometres across. Of course, it wasn’t the shadow matter itself that killed her. Just the storm it caused by its passage through the atmosphere.’
And not even that, Merlin thought. It was his decision that killed her; his conviction that it was more vital to save the first egg, the one falling into the storm’s eye. Afterwards, discovering that there was no gamma-ray point there, he had realised that he could have saved both of them if he had saved Pauraque first.
‘Something that massive, and that small . . .’ Gallinule paused. ‘It can’t be a moon, can it?’
Sayaca turned away from the sunset. ‘No. It’s no moon. Whatever it is, it was made by someone. Not the Huskers, I think, but someone else. And I think we have to work out what they had in mind.’
Nervously, Merlin watched seniors populate the auditorium - walking in or simply popping into holographic existence, like card figures dropped into a toy theatre. Sayaca had bided her time before announcing her discovery to the rest of the expedition, but eventually the three of them had gathered enough data to refute any argument. When it became clear that her news would be momentous, seniors had flown in from across the system, leaving the putative hideaways they were investigating. A few of them even sent their semblances, for the
simulacra were now sophisticated enough to make many physical journeys unnecessary.
The announcement would take place in the auditorium of the largest orbiting station, poised above Ghost’s cloud-tops. An auroral storm was lashing Ghost’s northern pole, appropriately dramatic for the event. He wondered if Sayaca had scheduled the meeting with that display in mind.
‘Go easy on the superstring physics,’ Gallinule whispered in Sayaca’s ear, as she sat between the two men. ‘You don’t want to lose them before you’ve begun. Some of these relics don’t even know what a quark is, let alone a baryon-to-entropy ratio.’
Gallinule was right to warn Sayaca. It would be like her to begin her announcement by projecting a forest of equations on the display wall.
‘Don’t worry,’ Sayaca said. ‘I’ll keep it nice and simple; throw in a few jokes to wake them up.’
Gallinule kept his voice low. ‘They won’t need waking up once they realise what the implications are. Straightforward hiding’s no longer an option, not with something as strange as the Ghost anomaly sitting in our neighbourhood. When the Huskers arrive they’re bound to start investigating. They’re also bound to find any hideaway we construct, no matter how well camouflaged.’
Zima Blue and Other Stories Page 21
