"It's really nice and warm here, I thought it seemed cold when I arrived," I had slept so well; I felt a mixture of relief and - hunger.

Daniel and Vuud and I were marching over to the dining area about a quarter of a mile away. Same black, dripping, rough edged rock, but now they just seemed solid and part of a relatively benign landscape.

Vuud said, "You must control the temperature as it's quite pleasant, but where does the heat come from?"

We sat down with ...