I couldn’t sleep last night.

Harold and Edna stayed until almost midnight. Betty finally fell asleep on the couch. I turned off the television after the second re-broadcast of the moonwalk footage and sat in the kitchen with this notebook until 2 AM.

I kept thinking about the specific texture of the moment. The grainy television image, the voice coming through the speaker, the careful steps. Armstrong described the surface as “fine and powdery” and said his boots left prints about an eighth of an inch deep. Aldrin called it “magnificent desolation.” These are the first words from the first people to visit another world, and they sound like what they are: careful observations, field notes, the first entry in the log of a world that had never been visited before.

I’ve been keeping this notebook for twelve years. Sputnik in 1957. I was 32 years old. I went outside in my bathrobe to look at the sky.

I’m 44 now. Betty and I never did have children, which is something we stopped discussing years ago and which is fine, mostly, though I notice it at moments like this — moments when I think about what I’d tell them. What I’d want them to know about watching all of this happen.

I’d say: pay attention to the things that seem impossible. Not to be discouraged by them, but because the impossible things are where the interesting work is happening. Somebody thought that putting a satellite in orbit was impossible in 1950. Somebody thought that a man in space was impossible in 1955. Somebody thought the Moon was impossible when Kennedy said it in 1961. And then, one piece at a time, people figured out how to do the impossible things, and now two men are on the Moon.

The impossible things are the things worth watching.

It’s 2 AM and I’m going to try to sleep. The astronauts are sleeping on the lunar surface — they were supposed to rest before the EVA but I don’t know how they managed it, knowing where they were.

Maybe the same way I can’t manage it now. Too aware of being in a place no one has ever been.