In the sunlit view through the time-reversed camera, Ramiro could see the broken ring of hills directly beneath the Surveyor, their eroded peaks casting long shadows to the east. Azelio had been ecstatic when he’d found this site, with the strange confluence of ancient dust flows that its peculiar topography had allowed. Ramiro didn’t pretend to understand the details, but over time the central valley appeared to have trapped wind-borne detritus from at least four different sources. From on high, the variety in the soils was impossible to miss, with great splotches of competing hues laid over each other like a mess of dyes spilt from a child’s paintbox. But though the colours were layered they remained distinct, which suggested that the whole arrangement was stable. The Surveyor was a great deal heavier than the probe, but if these deposits were prone to subsidence they ought to have shown more mixing under their own weight.

The temperature in the cabin had barely changed since they’d entered the planet’s atmosphere. Ramiro didn’t want to grow complacent; no one would forget the near-fatal surprise that the Object had held for its first visitors. But if a mismatch in Nereo’s arrow was a guarantee of mutual annihilation, the arrows of time were more pliable. On this world of lifeless dust with its almost timeless landscape, it did not seem too much to hope for that two opposing directions could coexist.

‘There’s the probe!’ Agata announced excitedly, pointing to a dark elliptical splotch. It was hard to distinguish the thing itself from its shadow.

The Surveyor was descending at a constant rate, leaving the cabin subject to Esilio’s full gravity – about a third higher than the home world’s. That standard was usually taken as the limit for prolonged acceleration, on the assumption that the ancestors’ physiology had adapted to it over the eons. But the travellers had coped easily enough with far lower gravity than the ancestral norm, and Ramiro did not believe that the settlers would be troubled by this minor increase.

Azelio said, ‘I can hear the wind.’

Ramiro strained his tympanum. It was hard to distinguish it from the sound of the cooling system, but the gusts were sharper, rising and falling less predictably.

The altitude displayed on the navigation console dropped below one saunter. As Ramiro watched the wind whipping dust across the ground, he began to discern an almost perfect dark circle with a wide penumbral ring, straight below the camera. He would have sworn it was the Surveyor’s shadow, but that made no sense: the sun wasn’t overhead.

A warning appeared below the image: the ultraviolet glare scattered back from the ground was approaching unacceptable levels. Even though the engines’ beams were splayed out to the side – and the camera was counting photons emitted, not received – too much irradiation could damage the sensor. Tarquinia closed the protective shutter and the image turned black.