The Arrows of Time

‘The trial isn’t finished yet,’ Azelio stressed. ‘There’s still a chance that this could be a temporary hiatus.’

‘Right.’ Agata understood now why he’d called on her to help him with the measurements: he was trying to keep the results from Ramiro for as long as possible, in the hope that something would change.

Azelio knelt down and continued his inspection; Agata did the same. As she turned the revelation over in her mind, she was surprised at her own equanimity. After six years away from the mountain the conflict that they’d come here to remedy seemed remote and petty. If they really could rid the Peerless of Medoro’s killers by showing that a settlement was viable, she’d certainly relish that victory – but between the light-deflection measurements and her work on the vacuum, she already found it impossible to think of her time here as wasted.

But Azelio had no such consolations; he was only here in the hope of making the mountain safer for the children he’d promised to protect.

On their way to the next plot Agata asked him, ‘Is it the composition of the soil? Or is it the arrow?’

‘I can’t say for sure,’ Azelio replied.

‘Can’t you guess?’ Agata pressed him.

He said, ‘The spectra suggest that at least two of the soil types should have had everything the wheat needed.’

‘So it probably is the arrow?’ There was nothing inimical to life about the mere presence of a conflicting arrow; the crew had survived it perfectly well, thanks to their store of food with its unambiguous origins and their undiminished ability to rid their bodies of excess heat. Esilio even accepted their excrement without complaint, however bizarre the material’s fate would seem to a time-reversed observer. But the plants’ uptake of nutrients relied on interactions between their roots and the native soil at a microscopic level, and there was no guarantee that the two systems, left to themselves, would simply sort out their differences.

Azelio wasn’t ready to give up hope of a simple agronomic solution. ‘We could try mixing the most promising soils,’ he said. ‘Or we could look for better conditions elsewhere. If it’s the arrow, that’s the end of it.’

Agata said, ‘I’ll defer to your expertise on soil chemistry – but when it comes to the arrow, let me be the judge. The problem still might not be insurmountable.’

‘Really?’ Azelio buzzed sceptically. ‘You can’t even sweep your own floor any more. How are you going to reach into the ground and persuade every speck of dust that it’s mistaken about the route it’s taking away from the entropy minimum?’

Agata had no answer to that. But if she couldn’t change the brute facts, the cosmos wasn’t taking sides in this clash: it simply had no choice but to reconcile everything it had brought together. If there had to be an accommodation between Esilio’s arrow and the Surveyor’s, the trick would be to find a way to make the crop’s failure even more improbable than its success.

Ramiro must have made a choice, Agata realised, not to seek constant updates on the state of the crops. Warned that there could be problems at the start as the plants adapted to their new conditions, he’d stepped back and left it to Azelio to monitor their health, and to offer a verdict only once it was warranted.

But Ramiro wasn’t blind, and as the flowers ceased unfurling and the stalks began to wither, Agata could see that both men were losing hope.

Bell after bell, day after day, she sketched elaborate diagrams for machines to manipulate the soil’s properties. Chemically, each mineral grain was no different from that of an equivalent on the Peerless or the home world. Physically, the distinction came down to the fact that soil on the home world had once been solid rock, while for Esilian soil, from her own point of view, that fate still lay in the future. Or in Esilio’s terms, the vast bulk of the planet’s soil had been eroded from rock… leaving two competing possibilities: that some small portion of it had actually been emitted from the roots of time-reversed stalks of wheat, or that those strange withered plants had failed to contribute anything before finally regaining their health and being carried away by the visitors.

Still, a plant knew nothing of the past and future of each grain of sand; the whole interaction with the roots had to make sense in the present. If she could find a way to measure the detailed distribution of thermal vibrations in the soil they’d brought with them, and then recreate that in the native soil, it would no longer be statistically reasonable for the plants to fail to absorb it.

To the naked eye, soil was just soil – and if the differences were microscopic, how hard could they be to erase? But when she took the most promising of her schemes and thought seriously about the practicalities, the measurements were close to impossible, the manipulations impractical, the computations prohibitive and the projected throughput so slow that a cubic scant of soil would have taken eons to process.