The Arrows of Time

‘Right! So now apply the same logic to starlight moving past Esilio’s sun. Suppose the light does bend. If four-space is flat, then the light won’t be following the shortest path, since in flat space that’s always a straight line. It will be on a path up on the valley’s slopes, where any tiny variation changes the length and throws the light out of phase. There are ways around that: we can postulate some mechanism that messes with the phase in exactly the right manner to favour the bent path – but that’s complicated, because as well as explaining what happens with the light, it needs to explain the force on an orbiting planet.

‘If four-space is curved, though, that does the job for everything. Light waves and luxagen waves, it makes no difference: if they’re following the shortest path in four-space, they’ll arrive in phase. That’s enough to bend the beam, and enough to make a planet swing around in its orbit.’

Azelio pondered this, and found nothing he could object to. ‘It makes more sense than I thought,’ he admitted.

Agata was delighted. ‘So what’s your conclusion?’

‘My own prediction, now,’ he declared, ‘is that the light won’t bend at all. I can see why you think it would make things too complicated if you had to account for the bent paths of both light and matter, in flat space. So the simplest solution would be to keep space flat, but have light unaffected by gravity.’

Agata was on the verge of embarking on an account of how this would violate conservation of energy, but she stopped herself; she’d reached the point where it would be more economical to let the results speak for themselves. ‘Do you want to put two loaves on it?’ she suggested.

Azelio feigned shock. ‘The shape of the cosmos is at stake… and you want to swindle me out of my rations?’

‘Who’s swindling you? You can check all the data yourself. You can ask Ramiro to audit the software.’

Azelio considered the offer. ‘If the light goes straight, you pay me; if Lila’s predictions are confirmed, you win. Anything else – including Vittorio’s theory – is a draw.’

‘Agreed.’

‘Two loaves, then,’ Azelio confirmed. ‘You’re on.’

‘Is there something that needs monitoring while you’re waiting for the stars to align?’ Ramiro asked Agata. ‘I’m on watch all night – it wouldn’t be any trouble.’

‘There’s nothing like that,’ she replied.

‘Then why not get some rest?’

Agata looked up from her console. ‘I can’t just shut off my mind in the middle of this.’

Ramiro stretched his shoulders and swivelled around to face her. ‘The star trails will still be there when you wake. And we’ll be following the same orbit whether you’re sitting here fretting, or fast asleep in bed.’

‘That’s true.’

‘But… ?’

Agata said, ‘Why would I wait six years for the chance to do this, and then sleep through half of it?’

Ramiro buzzed. ‘Fair enough.’

‘I used to hold vigils outside the voting halls,’ Agata recalled. ‘I’d watch the people come and go, watch the tallies rising.’

He said, ‘So when you take something seriously, you try to make the most of it?’

‘Yes. Is that so strange?’ Agata tried to judge his mood, and decided to take a chance. ‘Isn’t that what you and Tarquinia are doing? Making the most of your friendship?’ Ever since Azelio had confided his own suspicions about the pair’s activities to her, Agata had suffered bouts of curiosity, but she’d never had the courage to ask the participants themselves about the experience.

Ramiro didn’t seem angered by the question, or embarrassed. ‘In a way,’ he said. ‘If I was back on the mountain, I’d be worried that I was doing the opposite: taking the drive to raise children and wasting it on something trivial. Here, I can tell myself that I have no chance of becoming a father, so it’s not a waste at all.’

Agata said, ‘Everyone but the Starvers accepts that it makes sense to have children without fission – so why not refine the process even further and select precisely the effects we want from it?’

‘Why not?’ Ramiro agreed. ‘As an abstract proposition, it sounds as sensible as separating out the parts of a plant instead of blindly eating the whole thing. We don’t have to swallow the poisonous roots when it’s the stem that actually tastes good.’

‘But why as an abstract proposition?’ Agata pressed him.

Ramiro hesitated. ‘The trouble is, even when the body can’t put things back together, it never forgets how they used to be joined.’

‘What do you mean?’

‘It makes me want children more than ever,’ he said. ‘It takes that ache that might have faded with time, and reminds me, over and over again, that it’s never going to be fulfilled.’

While they were in free fall the Surveyor could be oriented any way they liked, and Tarquinia had chosen to set the window facing the rim of the hemisphere of home-cluster star trails. As Agata’s vigil stretched on, she left Ramiro in peace, ignored the clock on her console, and just stared out through the window, waiting for the first sign that something solid and invisible had moved between her and the ordinary stars.