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.

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

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.

It would be especially comforting to believe that I have the answer to the question, What happens when we die? Does the light just go out and that's that-the million-year nap? Or will some part of my personality, my me-ness, persist? What will that feel like? What will I do all day? Is there a place to plug in my laptop?

Bodily fluids and solids are universally the most disgusting things we as human beings can come upon, but as long as they are inside us, it's part of you.

You won't see me writing about particle physics, or even planetary geology, or chemistry. I practically failed chemistry, and if I had to write a book in any of those areas, I don't think it would go well.

Viagra does have a physiological effect, but it doesn't make women feel aroused. Nowadays, researchers are looking at drugs that affect the central nervous system rather than blood flow to the genitals.