The Arrows of Time

by Greg Egan

  The approach was downhill, but the ground was uneven and strewn with small, loose stones. As Agata advanced the stones began jostling her feet, accelerated from a span or two away by time-reversed friction before coming to a halt against her skin. She glanced at Azelio; he was struggling to keep his footing, distracted by the bizarre bombardment.

  ‘Can you leave the plants here?’ she asked. Once they’d set the charge they’d be retreating to about this point anyway.

  ‘Good idea.’ Azelio set the pots down and they continued.

  When they reached the hillside Azelio switched on his coherer and played it over the pale brown rocks. ‘This is the target,’ he confirmed. He gestured towards the centre of the outcrop. ‘Anywhere about there should do it.’

  Agata handed him the bomb and waited for him to step away to a safe distance, then she started swinging her pick into the rock face. Small chips of stone flew out from the point of impact, stinging her forearms, but the rush of power and freedom she felt at the sight of the growing excavation was more than enough to compensate. In Esilian time, the chips were rising from the ground, propelled into the air by conspiracies of time-reversed thermal diffusion, just to aid her as she rebuilt the rock. What stronger proof could there be that the cosmos had a place for her, with all her plans and choices? One day it would kill her, but until then the contract was clear: hardship and frustration and failure were all possible, but she would never be robbed of her will entirely.

  She made the hole as deep as she could without widening it excessively; the idea was to confine the pressure wave within the rock as much as possible. When she stopped swinging, Azelio approached and held the bomb up against the opening. It didn’t quite fit at one corner. She set to work removing the obstruction.

  On the next attempt, the bomb’s cubic housing entered the aperture without resistance. Azelio gently pushed it deeper, then Agata aimed her coherer into the hole. There were some small gaps around the edge of the housing, but she didn’t think they’d be enough to dissipate the energy of the blast.

  She took the detonator from her tool belt. Ramiro had removed most of the original components and added a timer in place of the remote trigger. She started up the photonics and it ran a self-test; a short summary on the display panel reported that everything was working as expected. She plugged the detonation cable into the bomb, and tapped the switch to start the timer. The countdown showed nine lapses and falling. She rested the detonator in the mouth of the hole, then the two of them walked away.

  The loose stones harassed them again as they crossed the ground, and although the mild pressure on their skin was exactly the same as if they’d merely been dislodging the things, the timing was still disconcerting. Agata imagined the settlers’ children, raised with all of these quirks of nature and entirely unconcerned by them. She could sympathise with Ramiro’s discomfort, and she’d even shared it at times, but she felt no unease at the prospect of generations of innocent descendants of the anti-messagers living out their lives beneath the stars here. They’d have more comfort and freedom than anyone on the Peerless. So long as the crops grew.

  Azelio reached the plants; he squatted protectively in front of them. Agata turned to face the hillside.

  ‘I forgot to use my stopwatch,’ she confessed.

  Azelio hadn’t; he glanced down at his belt. ‘Still a bit more than two lapses.’

  Agata groped pre-emptively for an antidote to disappointment. ‘If this doesn’t go off, I think we could probably smash enough rock for a test plot by hand.’

  Azelio buzzed. ‘Not finely enough.’

  ‘I’m serious! We could start with a pick but then mill down the rock chips – like making flour from grain.’

  ‘If it does come to that, I’ll be reminding you that you volunteered. One lapse to go.’

  Agata felt her gut clench painfully. Her body was bracing instinctively for danger, but silence would be far worse.

  The hillside erupted with light. She flung an arm in front of her eyes, but with her rear gaze she saw her shadow stretched out behind her. The ground shook, and she hummed softly, remembering the blast that had taken Medoro. But this was its opposite: a force that might finally heal the mountain, as much as it could ever be healed.

  A warm gust of air struck her skin, carrying dust but nothing harder or sharper. The light had died; Agata lowered her arm and waited for her eyes to adjust back to the starlight.

  A great, loose mound of debris lay at the base of the hill. Azelio rose to his feet and put a hand on her shoulder; she realised that she was shivering.

  ‘It’s all right,’ he said.

  ‘Yes.’ At his touch Agata ached to feel more of his skin against her, but as an internal voice started weaving a story of the only fitting coda to this triumph, she shut off the absurd fantasy quickly, less afraid of any prospect of fission than of making a fool of herself with Azelio. ‘Let’s go see how it looks.’

  They approached the blast site cautiously. In the planning meeting Tarquinia had raised the possibility of a delayed secondary collapse, but as they drew nearer that looked less likely: the new rock face was almost vertical, but they hadn’t created an unstable cave or overhang.

  Azelio strode forward to inspect the mound. He knelt and picked up a handful of debris. ‘It looks fine enough,’ he announced warily. ‘There’s some coarser grit in there as well, but that shouldn’t matter.’ He turned to face Agata. ‘I think we’ve got a real chance.’

  Hearing the hope in his voice, Agata felt the sense of fulfilment returning more strongly, but it was stripped now of any desire to follow her instincts to the end. She had all she needed: Azelio’s friendship, and the satisfaction of having played a part in this scheme. It was enough.

  Azelio shone his coherer across the top of the mound. ‘That could feed a lot more than twelve plants,’ he said gleefully. ‘I’m just glad we didn’t have to do it by hand.’

  ‘Maybe the settlers will put their first farm here.’ Agata chirped, delighted by an absurd thought. ‘Maybe there are traces of them around, already – a few marks that they’ll unmake in the rock.’

  Azelio said, ‘If we can prove that they’re going to be here, will I still need to go ahead with the crop tests?’

  ‘Yes – or they’d never come!’

  ‘What if I lied and said I’d finished the tests?’

  ‘Then we’ll find some graffiti here, cursing you as the cause of the great famine.’

  ‘Which would shame me into doing the tests,’ Azelio replied. He raised the beam of his coherer from the mound to the rock face. ‘What’s that?’

  ‘Where?’ Agata couldn’t see anything.

  ‘About three strides up. It looks like writing.’

  Agata was sure he was joking, but she aimed her own coherer at the same spot, and the slanted light revealed the shadows of a host of narrow ridges. It really did look as if part of the stone had been carved away, leaving these lines in relief – on a surface that the blast had just exposed for the first time.

  ‘This is too strange,’ she said. She stepped onto the mound and walked across the fresh soil. She could feel herself leaving footprints, but unmaking some as well.

  On a closer view, it was clear that Azelio was right: the lines on the rock face formed symbols. The sides of the ridges appeared softened and eroded, as if a generation’s worth of future dust storms had left their mark. But she could still make out most of the message.

  ‘. . . came here from the home world,’ she read. ‘To offer thanks and bring you . . . courage.’

  Azelio said, ‘Who thanks whom for what?’

  Agata had never been less discouraged; she had never felt less in need of this grace. But here it was: for Ramiro in his darkness, for Azelio and Tarquinia, for everyone back on the Peerless, for six more generations of struggling travellers yet to be born.

  ‘It’s from the ancestors,’ she said. ‘They’re going to come here and write this. They’re going to come here to tel
l us that everything we’ve done and everything we’ve been through was worth it in the end.’

  23

  As Tarquinia stepped aside, Ramiro moved closer and took his turn examining the rock face. He hadn’t doubted his crew-mates’ word, but since they’d had no reason to be carrying a camera there’d been room for him to wonder if they might have over-interpreted some random pattern that had formed as the explosion fractured the hillside.

  ‘It does look genuine,’ he concluded. ‘Genuinely artificial, that is; don’t ask for my opinion on the authorship.’ After geology, he was going to have to add time-reversed archaeology to the list of disciplines he’d sadly neglected.

  ‘We should leave now,’ Agata insisted. ‘As soon as the Surveyor’s ready.’

  Ramiro turned away from the writing. ‘What about the wheat?’

  ‘The wheat doesn’t matter,’ Agata declared. ‘If there’s nothing left to fight about, there’s no reason for anyone to migrate.’

  Tarquinia was sceptical. ‘You really think the Council’s going to switch off the messaging system on our say-so?’

  ‘What will they need it for?’ Agata was beginning to sound exasperated. ‘This proves that we make it to the reunion! There’s no question of the Peerless being struck by a meteor – or tearing itself apart in a war. How can the Council claim that they need their system for safety and security once we’ve shown them a message that could only be written if we’re safe and secure all the way to the home world?’

  ‘They could argue that the settlers will write it,’ Azelio suggested.

  ‘What settlers?’ Agata fumed. ‘How could the settlers write something that would undermine their whole reason for being here?’

  ‘If the Council doesn’t take it seriously, it won’t undermine anything,’ Azelio reasoned. Ramiro wasn’t sure if that was circular logic, but as self-serving political rhetoric it did have a horribly plausible ring to it.

  ‘You’ve all lost your minds!’ Agata moaned. ‘If you think this isn’t genuine, tell me what would count as proof of authorship. A message encrypted with a key that we’re supposed to prepare now and then keep secret until we deliver it to the ancestors at the reunion? Even if we found something like that, you could still claim that the key might end up in someone else’s hands along the way.’

  Tarquinia said, ‘It’s not just a question of our own doubts; we have to take a broader view of this. If you and Azelio say the writing was there as soon as the rock was exposed, then I believe you – but all we’ll be able to show the Council is an image taken some time after the fact. That’s not even going to establish the sequence of events.’

  ‘My role here is as a witness for the messagers,’ Agata reminded her. ‘Why would I suddenly change my allegiance and start lying about something like this – just to try to get the system shut down?’

  ‘Twelve years isn’t sudden,’ Tarquinia replied. ‘They might think we corrupted you.’

  ‘Then what’s the point of doing anything?’ Agata retorted. ‘Why test the crops, when we might be lying about that, too?’

  Tarquinia tried a more conciliatory tone. ‘Look, I might be wrong: they might listen to all our testimony and conclude that the message really is from the ancestors. But we can’t take that for granted. We need to stay long enough to assess the new soil. It’s just a few more stints; what harm is there in that?’

  Agata looked away; she seemed to be struggling to calm herself. ‘You’re right,’ she said finally. ‘We came here to see if Esilio was habitable. And you risked your life for this experiment; it would be foolish not to wait for the results.’

  ‘We’ll spend some time imaging the site every way we can,’ Tarquinia promised. ‘We’ll gather as much evidence as possible to put to the Council. Then Azelio can plant his crop – and whatever the outcome, it won’t take away from the significance of the message.’

  ‘That’s true,’ Agata agreed.

  Hearing the disillusionment in her voice, Ramiro felt a pang of guilt. She’d run all the way to the Surveyor in a state of ecstasy, convinced that she’d just been handed the solution to all of the Peerless’s problems. He couldn’t fault her sincerity, or the generous spirit in which she’d brought him the news. She really had believed that it would spare him from the prospect of dying on this benighted world.

  But ever since he’d seen the writing for himself, he’d been unable to stop wondering if the message suited him too well. As far as he could recall, he’d never consciously planned to commit any kind of hoax – exploiting Agata’s longing to commune with the ancestors in the hope that in her innocence she’d sell the lie convincingly to the people back home.

  What he didn’t know was exactly what his lack of preparation meant. The words were there, Agata had seen them, nothing could change that now. But with every moment that passed it seemed more likely to him that the ancestors had nothing to do with it, and that he would find a way to write the message himself.

  Ramiro winced. ‘Please don’t do that.’

  Tarquinia ignored him and continued to palpate his abdomen. ‘You definitely have some kind of mass in your gut. Maybe we should think about cutting it out.’

  ‘Don’t be so dramatic. It will pass through me soon enough.’

  ‘Not if the wall of the gut is paralysed.’

  ‘I think I’ve had something like this before,’ Ramiro lied. ‘When I was a child. It only lasted for a couple of days.’

  Tarquinia gazed down at him, puzzled and concerned. ‘I’d thought we’d passed every influence we had back and forth to each other, long ago. Where does a new disease come from, after six years in isolation?’

  ‘Maybe I caught it from the settlers,’ Ramiro joked. ‘Maybe the first time-reversed influence evolves here, shortly after they arrive.’

  ‘No eating, no work, just rest. Is that clear?’

  ‘Yes, Uncle.’

  Tarquinia gave him a stern, reappraising stare. ‘If you’re faking this to get out of helping with the cooling system—’

  ‘Faking a lump in my gut?’ he protested. ‘Seriously, I won’t eat, I promise. Last time I tried it made the pain unbearable.’

  ‘All right.’ She squeezed his shoulder. ‘I’ll be wearing an audio link, so if you need anything just yell.’

  ‘Thank you.’

  When she’d gone, Ramiro turned in his sand bed, trying to find a half-comfortable position. The smear of sealing resin he’d spread through the loaf had been tasteless and odourless, but the effects had exceeded his expectations. All the other substances he’d tried in similar doses had either been inert or had caused him to vomit up the meal immediately. So long as his gut did eventually regain the power of peristalsis, he’d have no qualms about sharing this ‘influence’ with Agata: she’d be laid low for a day or two, but the precedent of his own recovery would spare her from too much mental anguish.

  All the rest would be down to timing. Azelio would want to watch over Agata, the way she’d cared for him when he’d been injured, and if he’d finished his work with the test crop there’d be no reason for him to return to the blast site.

  Tarquinia would be the hardest witness to avoid. Ramiro didn’t want to risk raising her suspicions by trying to manipulate her movements – let alone poisoning her – so he’d have to contrive an innocent-sounding reason to be away from the Surveyor for at least two bells. Either that, or tell her everything.

  His gut convulsed; he rearranged himself, curling around the site of the pain, trying to take the pressure off the lump of trapped food. If he was the author of the message, nothing would intervene to prevent him from carving it before the Surveyor departed, but that was no guarantee that his ruse would remain undiscovered. He couldn’t presume that Tarquinia would approve of the deception but, even if she did, the mere act of widening his private scheme into a conspiracy could only weaken the chance that the crew would convince their interrogators back on the Peerless. Agata would be the passionate advocate for her own interpre
tation, while Azelio and Tarquinia would be more sceptical but still able to give honest, credible testimony. Why ruin that by forcing Tarquinia to lie?

  Of course, Greta would assume that he was behind the whole thing before he’d even spoken a word. But so long as the Council hadn’t abolished the popular vote entirely, it was not beyond hope that the expedition’s claims could sway enough travellers into changing their position. Not even a message in light from the time of the reunion could be authenticated beyond doubt, but if people were willing to give this message in stone any credence at all, it could shift the balance of their anxieties and prompt them to heal the rift that the system had created.

  The strangest part was that everyone on the mountain would already know what collective decision they’d take. So the moment the Surveyor had re-established a link with the Peerless – long before the crew had been questioned in person and their individual stories tested and compared – he would discover whether or not the hoax had been in vain.

  ‘Aren’t they beautiful!’ Azelio enthused.

  ‘Well, they’re not dead,’ Ramiro allowed. After three stints rooted in the debris of the explosion, all twelve plants still displayed a modest selection of bright flowers – which was more than any of the earlier trials had achieved.

  ‘They’re growing,’ Azelio assured him. ‘Every one of them.’ He knelt down near the start of the row. ‘This seedling is half as tall again as it was when I put it in.’ He gestured along the progression of plants. ‘In fact, each one of them has come close to matching the way its neighbour appeared at the start. I know that doesn’t make much of an impression: everything you see now in the first eleven specimens is something you’ve seen before from the second to the twelfth. It’s almost as if you’ve just shifted your gaze slightly. But the figures bear it out: we’ve made the soil fertile.’