The Arrows of Time

Note to Readers

The Arrows of Time is the third volume of a trilogy set in a universe with laws of physics that are very different from our own. The protagonists belong to a species whose biology, history, politics and technology – as revealed in the previous books – bear crucially on everything that follows. Accordingly, anyone approaching this volume is strongly advised to read the preceding volumes first.

1

From her hilltop post, Valeria swept the telescope’s field of view methodically across the barren plain. The grey rock showed few features in the starlight, but so long as she didn’t rush the task and left no gaps in her search, the kind of change she was looking for would be hard to miss.

She knew she was done when she’d made a full circle around the scope’s mount, bringing her feet back to a patch of rough ground that she could recognise by texture alone. Done and ready to begin again.

Two bells into her shift, Valeria could feel her concentration faltering, but whenever she was tempted to abandon the mind-numbing routine she thought of the incident outside Red Towers. The watcher there had seen a speck of light in the distance, small but growing steadily brighter. His team had reached the fire within a chime or two, and by drawing out its heat into three truckloads of calmstone sand they’d succeeded in extinguishing it. The Hurtler that struck must have been microscopic, the point of ignition shallow, the field of flame relatively small – and some scoffers had gone so far as to insist that there must have been similar strikes before, unobserved and untreated, that had come to nothing. But Valeria was sure that between the spot fires that would fizzle out on their own and the kind of unstoppable conflagration that would simply vaporise everyone in sight, there was room for the watchers to make a difference. If a planet-killer struck, it struck, but it wasn’t futile for people to try their best to fend off disaster for as long as possible.

The clock beside her rang out the last bell before dawn. Valeria gave herself a break, rolling her neck and taking in the view untrammelled by the scope’s restrictions. At the foot of the hill the response team, her co among them, were napping in their sand trucks. Gemma had risen now, bright enough to hide most of the stars, but seven Hurtlers shone in the grey half-light: seven streaks of colour, scattered but parallel, each one displaying perfect mirror-symmetry across its dark centre. These ghostly spikes were lengthening slowly, their violet tips just perceptibly in motion, proof that they hadn’t even been near misses. If a planet-killer was on its way, there’d be no elegant pyrotechnic warning.

But nor would the opposite fate come with portents: if a real solution to the Hurtlers was imminent, the moment of salvation would pass without distinction. If such a feat was possible at all then it was due to be achieved any day now, but there would be no signal from the travellers on the Peerless, no manifestation in the sky, no evidence of any kind.

Still, Valeria took the Hurtlers themselves as proof that the travellers’ first goal was attainable: one object really could possess an infinite velocity relative to another. The history of each Hurtler was orthogonal to her own: the tiny rock’s eons of ancient darkness and its fiery passage through the thin gas between the planets all came and went for her in an instant, with nothing but the time lag for the light to reach her prolonging the spectacle. If the Peerless really had been accelerating steadily for the past year, its engines firing without mishap, its relationship to her would soon be the same as the Hurtlers’. Having entered that state, the travellers could maintain their course for as long as they needed, and whether the need was measured in generations or in eras, from her point of view they would live out their lives in the same blink of her eye, regardless.

Valeria stepped away from the telescope and followed the lines of the Hurtlers to their notional vanishing point. Watching from Zeugma, she’d seen the blaze of flaming sunstone as the mountain sped away in exactly this direction. She held up her thumb, blotting out the point in the sky where the Peerless had been heading – blotting out a line that stretched away from her for an immeasurable distance. At the moment of orthogonality, that line would contain the entire history of the travellers from the day they shut off the engines to the day they had reason to return.