Gravity disappears again, and we rise up off the floor like spooks from a grave. It's like the Rapture in here every thirty seconds.

The human head is of the same approximate size and weight as a roaster chicken. I have never before had occasion to make the comparison, for never before today have I seen a head in a roasting pan.

Sexual desire is a state not unlike hunger.

For the scientists, they're kind of puzzled and pleased that somebody finds their work interesting. It makes it fun for me. I feel like I've sort of turned over a stone that hasn't been turned over.

If you could really guarantee that the money would be spent on something more worthwhile, I'd say, absolutely, scrap the space program, but it never works that way.

Life contains these things: leakage and wickage and discharge, pus and snot and slime and gleet. We are biology. We are reminded of this at the beginning and the end, at birth and at death. In between we do what we can to forget.

In 'Packing for Mars,' I tried to convey the importance of getting young people interested in science.