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.

He was here because it was one of the few solid, stable places left on the planet.

Earth, from space, looked like a jigsaw puzzle, or maybe like a pan coming to the boil, black continent pieces outlined by blood red.

It was astonishing how events had accelerated, towards the end. It had been faster than anyone had believed.

He wondered how long he’d last. How much of it he would see.

…Did you know I was alive when Apollo 8 flew by the Moon? The astronauts, Borman, Lovell and Anders, were the first humans to see the Earth whole. They thought it was blue, and fragile, like a Christmas tree ornament. Well, they were right. Fragile.

I know you think I’m crazy to stay.

You know, one of the most beautiful theories of the history of the Earth was published by a guy called the Reverend Thomas Burnet, in England in the seventeenth century. Burnet said the Earth originated from chaos, a fluid mass of particles of matter. The particles grew together to form a perfect sphere with a smooth surface, concentric shells of liquid and air around a solid core. But there was an oily fluid in with the water, and when dust mixed with it, it formed a firm and fertile envelope over the layer of oily water.

But the sun’s heat made the fertile shell dry and crack. The waters below boiled, vaporized and exploded, and the Earth was flooded. When the agitation settled out, the waters drained back to the low places. Fragments of Paradise were left sticking up as continents and islands.

And that’s the world I was born on.

Eventually, though, flames would come to purify the Earth, and it would return to its paradisical state, and finally merge with God by becoming a star.

Well, it was a theory. That’s the way geology used to be, kid, a thing of dreams and fancies unsullied by brute fact. We only got into all that science stuff when the industrialists came along and started asking where they were going to find coal and iron ore and oil, and why the hell is the world so complicated anyhow?