Poseidon's Wake

by Alastair Reynolds

  ‘Depends on your definition of close.’

  ‘We can cross water if we need to. There are rafts – big enough for all of us.’

  ‘They’d better be. We’re coming up on the wheel now – this may be your one chance for a good look before we ditch. Do you want to see it?’

  ‘More than anything in the world. I’ll be there in a moment.’

  He had reached the Risen. He knelt by Dakota, glad when her pink-rimmed eye made contact with his.

  ‘We’re through the worst of it, I think. Icebreaker blew up and we ran into the shock wave. But other than the splashdown, we shouldn’t hit anything you can’t handle. Are you all right?’

  ‘I was always the hardiest of us, Kanu. Hector is alive, though weak. But Lucas has passed into the Remembering.’

  It took only a glance to confirm this news. Hector looked drowsy, but his gaze still tracked Kanu and a twitch of his trunk signalled the presence of life. The other Risen’s eyes were open but quite unseeing. Kanu stared at the mountainous swell of his ribcage. It remained as still as a rock.

  ‘I’m sorry.’

  ‘We are stronger than you in so many ways, yet weaker in others. How far are we from the sea?’

  ‘Pretty close now. When we ditch . . . well, I’ll do what I can for everyone. Best stay in the hammock until we hit water.’

  ‘I shall.’

  Kanu glanced out through the window again. The waters ruffled by the shock wave were returning to their former stillness. He tried to estimate their height from the hammered texture of the wave-tops, but it was impossible. And there was nothing down there, no rock or living thing, no trace of human presence, to offer the slightest hint of scale.

  ‘You’re missing the show,’ Nissa said.

  He returned to the command deck, trying to put aside thoughts of what lay ahead by confining himself to the present moment, to the spectacle the universe had seen fit to let him witness.

  Half of the wheel was hidden to him, lost beneath the water’s surface. The visible portion arched from the ocean in two places, separated by the two hundred kilometres of the wheel’s diameter. The nearest of those two points was only a few tens of kilometres from Noah. They were circling it now while also losing height – and still coming down harder and faster than Kanu would have wished. The upper portion of the wheel was not visible at all, but that owed less to Poseidon’s curvature than to the presence of so much atmosphere in between, hazing out detail and contrast. Looking up, he could track the ascent of the nearest arc, soaring almost vertically to begin with but gradually evidencing its great circular curve as it pushed higher and higher, finally cresting the atmosphere and vaulting into open space. There was much less air to obscure his vision when he looked to the zenith and the wheel’s arc was traceable far past its maximum height. He followed the fading white scratch until it vanished into the haze, pointing to the place on the horizon where the rest of the wheel must lie.

  They continued descending. The wheel’s tread was a kilometre across; its rim had about the same depth. From space they had detected a suggestion of dense patterning on the surface, a complex, shifting backscatter of metallic traces. Now their eyes were all the equipment they needed to gather more data. The wheels only looked smooth from a distance; up close they bore a finely printed text. A pattern of grooves had been cut into both the tread and the rim, as sharp-edged as if they had been lasered yesterday. On the tread, the patterns consisted of horizontal grooves, one above the other, running nearly the full width of the wheel. The grooves were only straight when averaged across their length. On a scale of a few metres, they exhibited a series of angular changes of direction, sometimes doubling back before resuming course. Each groove appeared distinct from those above or below it, but it was impossible to look at more than a few at any one time. There were no more than ten metres between each groove; if the wheel’s circumference was somewhere in the region of six hundred kilometres, then there could be many hundreds of thousands of these grooves – more grooves than there were words in a book. The rims, meanwhile, carried about a hundred concentric grooves – circular statements which Kanu presumed continued all the way around the wheel. On the wheel’s concave face, too, were yet more angular grooves.

  Kanu reminded himself that there were other wheels all over the planet. Some intuition told him that the wheels must each contain distinct patterns. If each wheel was a book, then Poseidon was a library.

  ‘I’m no expert,’ he said, ‘but that looks like the same sort of writing they found on Mandala.’

  Nissa nodded. ‘No surprise if the M-builders were here.’

  ‘The same language,’ Swift said, ‘but not necessarily serving the same function. Eunice was only able to trigger the Mandala because the syntax provided a set of operating rules. This has to be something different.’

  ‘Operating rules for the wheels?’ Kanu speculated. ‘We know they’re multifunctional – they can become the moons, if needed, or the moons can turn into wheels.’

  ‘Perhaps,’ Swift said.

  ‘You think it’s something else.’

  ‘If the Terror taught me one thing, it’s that there are answers here – otherwise why guard against the likes of us? Perhaps a history, an accounting of what became of the M-builders. The wheels may encode that history, collectively or individually, and we have been granted permission to read it.’

  ‘Then it’s a pity we don’t have the lexicon,’ Nissa said. ‘Or did Eunice share that with you during your blissful communion?’

  ‘No – there wasn’t time for anything like that. But you are right – she would know what to make of this, I think. Better than I do, at any rate. I think I may have outlasted my usefulness to you both.’

  ‘We’ll be the judge of that,’ Kanu said. ‘Anyway, you’re here for the same reason I am – to see and learn. So make the most of it.’

  ‘Believe me, I am doing my utmost.’

  As they spiralled down, Nissa strove to bring them closer and closer to the point where the wheel rim thrust from the waters. The scale of it had been overwhelming enough in abstract terms, but now Kanu had the sense of some stupendous cliff or pillar rising from the sea, a thing of imperturbable mass and solidity. They could dash Noah against it and not even leave a blemish.

  ‘One more circuit, if we’re lucky,’ Nissa said. ‘Are the Risen ready?’

  ‘It’s just Dakota and Hector now. I’m afraid Lucas didn’t make it.’

  She must have heard something in his voice. ‘You’re sad about that, aren’t you?’

  ‘I don’t know. A little while ago I’d have given a lot to see the three of them dead. But I can’t rejoice.’

  ‘Maybe Lucas was the lucky one – he got it over with quickly.’

  ‘We’ll see.’

  Chimes sounded; Noah had detected the approach of the sea’s surface, thinking in its simple-minded way that it was still ferrying people from orbit to Crucible.

  Whatever happened, it would not be long now until they hit the water.

  CHAPTER FORTY-NINE

  Mposi was not yet committed to entering the thresh of moons, but it would not be long before they ran out of time to turn around. ‘We can go a little deeper,’ Vasin said, ‘but it’ll gain us very little in terms of our view and it probably won’t help them at all. The best we can do – the only responsible thing – is document their actions from this distance, so that at least we have a chance of telling someone else about them.’

  ‘You’re not dead,’ Eunice said, ‘until you’ve left a crater big enough to stick a name on.’

  ‘They won’t leave much of a crater on a waterworld,’ Vasin replied brusquely. ‘Anyway, what do you propose? This is a heavy lander, built like a squared-off brick. We are not remotely atmosphere-capable. And that’s not a question of skill or daring – it’s a basic limitation of the vehicle. Drop it into
air, it’ll rip itself to pieces.’

  ‘If we keep our speed low, we can hold the aerodynamic stresses at a safe level.’

  ‘Perhaps. But the engine’s not rated to run in atmosphere, and we’d need to fire it continuously to keep our speed low enough to avoid structural overload – basically we’d be descending on a pillar of flame. That’s fine in the upper atmosphere, but as soon as it thickens up, we’d run into significant thermal transfer. We’ll superheat the air we’re descending into, and on top of that, our exhaust plasma will back up all the way to our tail quicker than you can blink. It’s easy to say that we should have brought something that can fly in air – but when we left Travertine, this wasn’t exactly where we thought we’d wind up.’

  Eunice absorbed this without further argument – it was clear to Goma that she accepted the essential truthfulness of Vasin’s statement; just as it was clear that Eunice would not have rested without exploring all the options, however slight they might appear.

  ‘Then there’s nothing aboard – no escape pod or capsule – that we can send down into the atmosphere?’

  ‘Nothing,’ Vasin said. ‘And believe me, I wish it were otherwise. But if they can hold out long enough for Nasim to get here, maybe we can do something for them.’

  ‘You should see this?’ said Loring.

  Vasin looked more irritated than intrigued. ‘Will it change our options?’

  ‘Not certain? Changes something, for sure.’

  Ve had arranged a display of the space around Poseidon, collating data from both Mposi and Travertine. It was as up to date as the latency of time lag and sensors allowed, showing the relative positions of the moons and spacecraft with high accuracy.

  Something was happening to the moons.

  ‘Kanu passed through,’ Loring was saying. ‘We all saw it? Happened just as Eunice warned us? One of the moons chased down his ship, swallowed it, put them through . . . what did you call it?’

  ‘The Terror. The ultimate line in the sand, which the moon clearly deemed Kanu fit to pass.’ Eunice was rubbing at the welts on her wrist where she had been restrained. ‘But that didn’t surprise me – Dakota had already made the crossing, so why would it turn her back now?’

  ‘A million reasons,’ Vasin said. ‘Still – what’s the significance of this? Have you seen anything like this before?’

  ‘I don’t think so.’

  ‘You don’t think so?’

  ‘At my age, you become forgetful. But no, I believe this is new to me. Shall I speculate?’

  ‘The floor’s all yours,’ Vasin said.

  ‘Kanu was scanned by the M-builders the way the Trinity was and they’ve allowed him safe passage to Poseidon. But the moons see us as more of the same – just another extension of the same interested intelligence. They must recognise some basic kinship between us and them – something that indicates we share the same biological concerns and imperatives – for now. It’s allowed him through, so for the moment the gates are open. The moons are giving us clear passage.’

  ‘You can’t know that for sure,’ Ru said.

  ‘And your contribution to this debate is . . . what, exactly?’

  Still, it was true about the moons – they were not following their usual orbits, or rather their orbits had begun to bend, lining up into a single flat ecliptic. They had not yet settled into that configuration – it would take hours at the present rate of change – but the end-state could be easily predicted.

  ‘Ru’s right, though,’ Goma said. ‘That could just as easily be a final “keep out” as an invitation.’

  ‘Thank you,’ Ru answered, pushing her words through clenched teeth.

  ‘It’s of theoretical interest,’ Vasin said, ‘but it changes nothing. We haven’t suddenly become a different ship, and all the barriers to landing on Poseidon I’ve already mentioned still apply.’

  ‘Then we don’t,’ Eunice declared. ‘You said the ship isn’t built for atmosphere. But we could land on top of one of those wheels, couldn’t we? Give me a reason why that wouldn’t work.’

  ‘How about because it’s totally pointless? We still wouldn’t be able to get help to Kanu.’

  Eunice looked around the room, eyes wide with disbelief. ‘Give me a break, Gandhari. This ship is stuffed with supplies.’

  ‘Which would still be a hundred kilometres from the surface. The time it would take to climb down . . . if there was a way to do that . . . and then what?’

  ‘Lower supplies to them – rations, clothing, medical gear, whatever they need. Enough to keep them going until Travertine arrives. And if that doesn’t work, they can tie themselves to the rope and let us haul them back into space.’

  ‘One hundred kilometres?’

  ‘Why not?’

  Vasin sighed. ‘Because I reviewed the equipment manifest myself so I know exactly what we have aboard. We have docking tethers, surface-penetrating grapples and power winches. But the tethers won’t reach that far – we brought them to help us hook onto Zanzibar, if it came to that. I saw no need for longer lines on this trip, and I’m not even sure Travertine could have supplied them if I had.’

  ‘How long,’ Goma said, ‘is the longest tether?’

  ‘Forty, fifty – no more than that. They’re not made to be joined together, either.’

  ‘It’s not enough,’ Ru said.

  ‘Next time you put together a supply manifest,’ Eunice said, ‘ask for some help.’

  ‘Nobody could have anticipated this,’ Vasin said. ‘Not even you.’

  CHAPTER FIFTY

  Kanu had gone back to the two surviving Risen, who were still in their hammocks. ‘You should prepare yourselves,’ he told them. ‘There’ll be a bump, I think, but nothing worse than what we’ve already been through. How are you coping with the gravity? Do you think you can stand it?’

  ‘I believe the gravity may be the least of our problems, Kanu. I shudder to imagine the depth of water beneath us, that it can swallow half the width of that wheel. Have you seen it?’

  ‘Yes. It’s magnificent. And humbling. Whoever made it, they weren’t exactly lacking in confidence.’

  ‘No, I do not think they were. I saw some of it through the window. I would very much like the time to know it better – the time to study those writings. Do you know the strange thing, Kanu?’

  ‘This is all strange, frankly.’

  ‘Then let us talk of specifics. For as long as I can remember, I have wanted nothing more than to be here, inside the mysteries of Poseidon. Within the sentinel moons, having once more endured the Terror, close enough to see the wheels, close enough to understand them for myself. And yet now that I am here, I realise there can be no understanding. Not for me, at least. I gather information, but I was never intended to be anything more than a recording instrument, a conduit to transmit observations to the minds of the Watchkeepers. I am their eyes, a branch of their extended nervous system – nothing more.’

  Once again Kanu marvelled at the bony prominence of her forehead, holding back the force of her mind like the wall of a dam.

  ‘I think you underestimate yourself, Dakota.’

  ‘I think they would say that I have failed them. I might say that I have failed myself.’

  ‘No,’ Kanu said. ‘Not yet.’

  ‘You ought to despise me, knowing what I ordered done. But while there is time, I would like to absolve Memphis of any complicity in my actions. Should the opportunity present itself, I would ask you to present this information to your fellows – the other humans. If they find Zanzibar again, Memphis ought not to be blamed for the deaths of the Friends.’

  Kanu phrased his question as softly as he was able. ‘Because he was only following orders?’

  ‘Because there were no deaths. I deceived you. The hundred cold corpses? They were already long past any chance of revival. I told Mem
phis to use only those who could never live again.’

  Kanu nodded slowly – he had no means of validating this claim, but it did not strike him as a lie. She had continued to value and respect the Friends long before his arrival, and he believed that she felt genuine remorse for the humans who had perished during the time of troubles.

  ‘And if another hundred had needed to die?’

  ‘I trusted that my point would be adequately made by those first hundred.’

  He smiled. ‘It was.’

  ‘What became of me, Kanu, to bring us to this place?’

  ‘Nothing you need blame yourself for.’

  ‘I made questionable choices.’

  ‘So did we all.’ He set his jaw, tried to look confident in the face of dauntless odds – one of the oldest tricks in the book of diplomacy. The void was still inside him – it was going to take more than a few hours of his life to eclipse that darkness. But like a stiff new spacesuit, cumbersome at first, he was beginning to adjust to its presence. ‘We’ll be hitting the water very soon. The odds are that the ship isn’t in excellent shape, but we’ll do our best to hold it together.’

  ‘We always do our best.’

  The impact was hard, but perhaps not as bad as he had feared. After the initial bump, Noah’s momentum carried it through the water, bellying up and then settling into a level configuration. Water sizzled where it touched the still-hot hull and fanned out in butterfly wings of spray on either side. And then they were resting, with barely any rocking from side to side as the lander floated. Dakota and Hector began to extract themselves from their hammocks, Hector labouring over it at first, then appearing to find some of his old strength.

  Kanu went forward. Nissa was already out of her seat.

  ‘Well, we’re down,’ she said. ‘More than I was expecting when that shock wave hit us.’

  ‘We’re in one piece. How is the ship?’

  ‘I wouldn’t bet my life on it – or yours. If the hull’s as damaged as it thinks it is, we may not remain afloat for long.’