Greg Egan - The Arrows of Time

A short burst of data appeared on the console. Tarquinia chirped. ‘Number one’s made the jump!’

Ramiro waited for the next report, then scrutinised the figures. ‘It’s clinging on, and it hasn’t jammed.’ He wasn’t satisfied yet; it was still possible that the strings would become progressively twisted. The occulter rotated its body in opposite directions with each step, so all things being equal it ought to unwind as much it entwined, but he could imagine some configurations of the strings interfering with the process and favouring one direction.

But in the third report the torques were unchanged, and the fourth confirmed that nothing was escalating. The occulter was cycling its way up the rock face towards its target, tenaciously regaining the same equilibrium with every step.

Ramiro sagged across the desk. ‘I think I just aged another six years.’

Tarquinia said, ‘Better here than back on the Surveyor .’

‘That’s true.’ Ramiro had never thanked her for the lengths to which she’d gone to spare him that fate. He sat and watched her for a moment, wondering what she’d say if he raised it after all this time. But he suspected that it would only annoy and embarrass her if he told her that he knew what she’d done for him.

The second occulter flew over the edge, and recovered as well as the first. Ramiro was wary of becoming complacent — but it made no sense to reason about the machines’ fate without taking account of everything he knew of both the past and the future. The disruption would happen, that was close to a certainty, and the occulters’ behaviour had to be consistent with that. The cosmos was indifferent as to whether the solution of its governing equations described the Peerless obliterated by a meteor, or just a few conspirators managing to shatter a few mirrors. But even the most dispassionate mathematician who’d been told that twelve clockwork insects carrying explosives were crawling across the mountain towards the light collectors would have to accept that the second solution now appeared at least as viable as the first.

The third occulter reported success. The fourth, the fifth. Ramiro said, ‘When this stage is over, we should go and tell Agata and Azelio. They deserve to have their minds put at ease.’

Tarquinia was sympathetic, but not so sure that it would help. ‘Do you think Azelio would get any comfort from this?’

‘Once he’s confronted with the sheer improbability of a meteor arriving at exactly the same time as the occulters, it might change his perspective.’

The sixth occulter landed safely and commenced its upwards crawl. Tarquinia said, ‘After Agata and Azelio, we should break the news to the Councillors.’

‘Really?’

‘Just to taunt them,’ she stressed. ‘No details.’

Ramiro said, ‘Where’s the fun in that? They’ve known for three years that they were going to be defeated.’

‘I’m not sure that’s true,’ Tarquinia replied. ‘I think they convinced themselves that it would be a meteor. No defeat, no surrender, just an act of nature.’

The seventh occulter sent its report. Ramiro squinted at the numbers, confused. ‘What… ?’

Tarquinia leant closer to the screen. ‘It’s gone into the void. It fired the air jets to leave the slope, but then something jammed and it couldn’t get back.’

A second report arrived; the accelerometer showed the occulter in free fall.

Ramiro was numb. ‘That’s impossible. How can we lose one when we have no spares?’

Tarquinia said, ‘What if we change some of the targeting? Maybe we can take out two light collectors with one bomb – or three with two.’

Ramiro brought the target coordinates onto the screen. ‘How do we model this? Do we add the pressures from each shock wave?’

‘That will do, for an estimate.’

The estimate told them that the strategy wouldn’t work. The light collectors were spread too far apart, and the blast radius of each bomb was too small.

Ramiro was lost. ‘What is it that we don’t understand? Could one channel survive?’

Tarquinia considered this. ‘So one Councillor already knows what comes after the disruption? It’s hard to believe that they could keep that a secret from the others, and I don’t see how the politics would work: in the aftermath they’d just be despised by everyone for withholding the information.’

‘It’s not impossible, though.’

‘It’s not impossible, but I’m not going to rely on it.’

‘So what do we do?’

Tarquinia hesitated, then came to a decision. ‘I’ll go out and repair the occulter – clean the jets, change the air tank. It’s in free fall and we know the trajectory; it shouldn’t be too difficult to intercept.’

Ramiro fought down an impulse to volunteer himself; she’d have a far better chance of success than he would, if she could get out into the void at all. ‘Won’t the airlocks be guarded?’

‘I know a way out through the observatory,’ she said.

‘A way out that isn’t an airlock?’

‘It’s a chamber with two airtight doors,’ Tarquinia conceded, ‘but no one ever uses it to come and go. There are some small instruments that we operate in the void, and we slide them in and out on tracks to avoid all the rigmarole of going outside to tend to them.’

‘But a person can squeeze through?’

‘Yes. Just barely.’

Ramiro said, ‘We don’t know that it won’t be guarded, or monitored somehow.’

‘No. But we can be sure that every other airlock will be.’

‘How will you get access?’

‘I think I can talk my way into an observing session – and there are tools, cooling bags and air tanks there already, I won’t need to drag a lot of suspicious paraphernalia with me. All I need is a bell or two alone in the main dome, exploring some hunch about the disruption.’

‘A hunch that your colleagues will know must come to nothing, or the Council would have sent the results back three years.’

Tarquinia scowled. ‘No, it must come to nothing that’s recognised as vital in the next three days – but that doesn’t prove that the observations won’t be valuable later. I can invent some wild theory on my way to the summit. Believe me, I’ve seen the observing program – no one has any idea where to point the telescopes right now. The chief astronomer will be grateful for anything that looks even half plausible.’

‘So the instrument will be doing some automated sweep… while you’re out in the void fixing the occulter?’ Every part of this sounded desperate, but Ramiro had no better ideas. ‘Won’t you be tracked?’

‘If I go straight up from the summit and then arc around towards the plane of the base I can stay out of range of the systems tuned for accidental egress – and I certainly won’t have the signature to be mistaken for an incoming Hurtler.’ Tarquinia reached across the desk and took the link. ‘I’m going to need this to reprogram the occulter. We should have made it possible to talk to the things with a corset alone, but it’s no use complaining about a lack of foresight.’ She formed a pocket for the link then started dragging herself towards the door, then she saw the expression on Ramiro’s face.

‘We’ve both survived tougher jobs than this,’ she said. ‘I’m not going to die out there.’

‘I know, but—’

‘If I get arrested, just pretend to be shocked. Maybe there’ll still be something you can do – don’t assume that the whole plan’s dead just because they’ve grabbed me.’

‘All right.’

Tarquinia drew herself towards Ramiro and embraced him. ‘This is just a glitch,’ she said. ‘In a few bells I’ll be back here and we’ll be joking about it.’