We discussed the possibility that the Arch might still be functional, that even in its fractured condition it might still be able to detect Turk and allow us passage to Equatoria. That was almost certainly wishful thinking, however, and it would have been insanely risky to try an approach. As soon as we had landed, the ship detected two more fragments inbound from orbit. We couldn’t see them through the cloud deck, but the impacts created a shock wave that rattled the vessel’s hull even these many hundreds of miles away. An hour later the sea receded from the shore of the island, revealing ancient dead corals and black sand, then came rushing back in a surge that would have been catastrophic had there been any living thing in the path of it.

We could go back to Vox, I pointed out. The aircraft would do that anyway, automatically, once its fuel supply was nearly exhausted.

“There might be nothing left of Vox,” Turk said. The Hypothetical machines would have reached it by now.

Maybe. Probably. But we didn’t know what had caused the Arch to fail—maybe the same thing was happening to the Hypothetical machines; maybe they were disintegrating at the shore of the Ross Sea. If Vox was intact, it would still be capable of harvesting enough protein from the ocean’s bacterial blooms to support a small population.

“In that case they’ll be fighting each other for food,” Turk said. “And if all the Hypothetical mechanisms are breaking down, that’s still not good news.”

He was right, of course. The one Hypothetical technology we all took for granted was the intangible barrier that protected Earth from her swollen, aging sun. If that failed, the oceans would boil, the atmosphere would cook off into space, and Vox would end up as a dispersed cloud of superheated molecules.

But I was still in favor of heading for Vox Core when the time came. It was where (as Treya) I had been born. It would be a suitable place to die.

*   *   *

That night we witnessed the biggest impact yet. The ship alerted us to a large incoming object, and Turk adjusted the window so we could monitor the northwest quadrant of the sky. Despite the heavy cloud cover we could see the fireball as a moving blur of red light, followed by a sunset glow on the horizon. A substantial shock wave was inevitable, so we instructed the ship to anchor itself to the island by means of high-tensile cables fired into the bedrock.

The shock arrived as a solid wall of wind and hot rain. Our aircraft was pressure-tight and well anchored, but I could hear it straining against its cables—an agonized groaning, as if the Earth itself were in pain.