In a way, he was glad Jane wasn’t here to see this.

At least she had lived to see her grandchildren, growing straight and tall in the thin, clean air of the Moon.

But as for Henry, this was his home.

He had been in love with the Earth since the first time he opened a geology book, the first time he picked up a pebble from a beach and wondered how it got there. Now it was burning down around him, but he wasn’t about to abandon it.

He found himself walking on a layer of salt, white and bright in the smoggy twilight, that crunched under his feet.

This ocean had dried once before, though not in human history. And that had been significant. The ocean had ceased to buffer the local climate, feeding land areas with rainfall and reducing temperature swings. Forests had disappeared, to be replaced by dry grasslands, and the arboreal creatures had faced the choice of migrating, adapting, or dying.

One group of tree-dwelling primates was forced out of the branches that had hidden them from predators, and pushed onto the new grasslands of Africa, where they were going to need greater size and better locomotion and, above all, to get smarter.

They had never looked back.

Now, five million years later, a descendant of those frightened primates, dressed in a fragile spacesuit, stalked across the dried-up bed of the Mediterranean, looking for fossils and human artifacts, a few last treasures for the final Arks to the Moon.

5

And a final ten years…

Henry was standing on the Earth’s oldest rocks, and talking to his granddaughter, on the Moon.

…So here I am, Nadezhda, your honorary grandfather, sixty-five years old and no smarter than I ever was, waiting for the other shoe to fall.

I don’t suppose you know what that means. I can’t even remember how long it takes a shoe to fall on the Moon. Or if you wear shoes in those domes of yours.

Whatever.

I have instruments here, various sensors that show me what is happening inside the planet. I have a whole-Earth image here broadcast from one of your nearside observatories, I think at Kepler. I’m glad you can see the surface, from up there. The giant volcanoes blew off the crud, the Venusian atmosphere that was gathering, and who’d have thought that would be a blessing?…

He was in Isua, in west Greenland. He was standing on supracrustal rock bounded on both sides by granitoid gneisses: three point six billion years old. Babies for the Moon, but these rocks were the old men of Earth, the oldest, most stable place on the planet.

It seemed appropriate, to be here, now.

He was in a concrete, heat-insulated, pressurized bunker, which in turn was protected by what he would have called a force field when he was growing up, a piece of the smart stuff the kids on the Moon had been dreaming up. Technological evolution, force-fed by its environment, filling the niches.