Greg Egan - The Arrows of Time

‘What are you idiots doing?’ he called out.

‘Trying to see which footprints are ours,’ Agata replied gleefully. She jumped forward with her rear gaze fixed intently on the place where she’d been standing.

Ramiro was bemused, but then he observed her more closely as she took her next few leaps. Twice, as she jumped out of some indentation in the sand, it vanished. She and Azelio hadn’t actually made all the tracks that he’d attributed to them. Or not yet, they hadn’t.

‘Come and join us,’ Azelio said. ‘Some of these must be yours.’

Ramiro stayed on the top rung of the ladder, watching. Each time Azelio lifted his feet, scattered sand unscattered itself, grains sliding in around the places where he’d stepped to settle more evenly – though not always smoothing the ground completely. After all, Ramiro reasoned, it was possible to walk in someone else’s footprints, or to step several times in your own. It would only be the last footfall on any given spot – prior to the next occasion on which the wind levelled everything – that would unmake the imprint completely.

The crew had talked over possibilities like this, dozens of times. Ramiro knew he had no right to be surprised. But having sought a world where the dissenters could escape the tyranny of foreknowledge, what had he been given? A world where every step he was yet to take would be laid out before his eyes.

‘What happens if I try to walk on pristine ground?’ he asked.

‘Try it and see!’ Agata taunted him.

Ramiro descended to the bottom of the ladder, intending to move quickly and get the ordeal over with, but then his resolve deserted him. When he willed his foot to land on unblemished sand, what exactly would intervene to stop him? A cramp in the muscle, diverting his leg to its proper, predestined target? A puppet-like manipulation of his body by some unseen force too strong to resist, or a trance-like suspension of his whole sense of self? He wasn’t sure that he wanted to know the answer. And perhaps that was the simplest resolution: he would lack the courage to walk out across the surface of Esilio for the rest of the mission. He would cower in his room, leaving the work to the others, while he waited to return to the Peerless in disgrace.

Agata was watching him. ‘Ramiro, there’s nothing to be afraid of.’ She was amused, but there was no malice in her voice. ‘Just step off the ladder without thinking about it. I promise you, the world won’t end.’

Ramiro did as she’d asked. Then he looked down. He’d scrutinised the ground beforehand, and he was sure there’d been no footprints at all where his feet now stood.

He lifted one foot and inspected the sand below. He had created an indentation that had not been there before. That was every bit as strange to Esilio as the erasures he’d witnessed were strange to him.

‘How?’ he demanded, more confused than relieved.

‘You really don’t listen to me, do you?’ Agata chided him. ‘Did I ever tell you that the local arrow was inviolable?’

‘No.’ What she’d stressed most of all was a loss of predictability – but the sight of her and Azelio unmaking their footprints had crowded everything else out of his mind. Those disappearing marks in the sand might be unsettling, but if he could ignore them and walk wherever he pleased then they were not the shackles he’d taken them to be.

Still…

‘What happens if there are footprints that no one gets around to before the next dust storm?’ he asked Agata. ‘Ones that were there straight after the last storm?’

She said, ‘There can’t be a footprint untouched by any foot. I don’t understand the dynamics of wind and sand well enough to swear to you that there won’t be hollows in the ground that come and go of their own accord – but if you’re talking about a clear imprint, if we could keep our feet away from it, it simply wouldn’t be there.’

Ramiro pondered this, but it seemed much less dismaying than the kind of all-encompassing trail he’d originally feared. Esilio was a world where a certain amount of noisy, partial – and predominantly trivial – information about the future would be strewn across the landscape. There had always been plenty of trivial things that could be predicted with near-certainty back on the Peerless , and perhaps as many of them would be lost, here, as these eerie new portents would be gained.

Emboldened, he strode out across the illuminated ground, pausing every few steps to kick at the sand. Sometimes he simply pushed the dust aside; sometimes the dust applied pressure of its own, as it moved in to occupy the space his foot vacated. But that pressure never came out of nowhere: his feet moved as and when he’d willed them to move, followed by the dust but never forced to retreat. Nor were they thrust without warning into the air by a time-reversed version of the dissipation of motion into heat that took place when they landed.

By the time he reached the point where the coherers’ light gave out, he realised that the part of his brain that dealt with his gait and balance had come to terms with the ground’s bizarre behaviour as if it were nothing more than an unfamiliar texture: a kind of stickiness that rendered the soil a little unpredictable. He hadn’t slipped over once, or found himself rooted to the ground. On one level, he’d already taken the whole phenomenon in his stride.

Each time there was a dust storm the record of future movements would be erased, but even in a prolonged period of calm the footprints would overlap, conveying very little information. Compared with the crystalline certainties of the messaging system, it would be nothing: a novelty to which the settlers would soon grow accustomed.

Ramiro turned to Azelio. ‘Entertaining as this is, if you want to start the planting now I’d be happy to help.’

With so little wind about, Ramiro decided that it was worth opening both doors of the airlock so they could pass the plants straight through. Standing on the ground, he was at the perfect height to accept each pot directly from Azelio, instead of climbing up and down the ladder.

‘Be careful,’ Azelio pleaded.

The advice was redundant, but Ramiro took no offence. Azelio had been nurturing the things for six years – and tending to them while they were spinning in their tethered pods had probably been the most arduous task that any of the crew had faced.

Azelio brought out a dozen of the plants to start with. The wheat was a miniature variety that he’d succeeded in maintaining at a staggered set of stages in its growth cycle, allowing him to compress the time needed to assess its viability in Esilian soil. Instead of waiting a year to be sure that it could survive from sowing to harvest, in one-twelfth of that time they’d watch each representative plant advance from its initial level of maturity to that from which another had started.

Ramiro looked over the collection assembled beside the airlock. ‘And these are all going in the same kind of soil?’

‘Yes. Just a few saunters away. I’ve already chosen the spot.’

Ramiro followed Azelio across the bright ground of the Surveyor ’s domain and into the starlit valley. The two plants they were carrying put out a healthy red glow, but that didn’t do much to light the way. It was soon clear that, however well their eyes adjusted, they’d need to use the coherers they’d clipped to their tool belts – sacrificing their distance vision for the sake of surer footing. Ramiro tried to balance the confidence he’d gained in dealing with the soil’s peculiar forces with a suitable level of caution. There was no telling what Azelio would do to him if he stumbled and fell, crushing one of his darlings, even if ‘Esilio pushed me!’ was the honest excuse.