You can't be a writer and have nothing to write about. You have to have life experiences.

The StarTalks - while kids can watch them, they're actually targeted at adults. Because adults outnumber kids five to one, and adults vote, and adults wield resources, and adults are heads of agencies. So if we're going to affect policy, or affect attitudes, for me, the adults have always been the target population.

I like seeing how people have succeeded when others would have presumed they would have failed, and others just go along with whatever everyone else does.

If you need to invoke your academic pedigree or job title for people to believe what you say, then you need a better argument.

We only went to the moon for military reasons. The space enthusiasts of the day kept saying, "Oh, we're on the moon; we should be on Mars in ten years." That's if it was driven by exploration, but it's never been driven by exploration.

In the first year of a child's life we teach them to walk and talk. And then for the rest of their lives we want them to sit down and be quiet.

If you find life on Europa [Jupiter's moon], like, what would you call it? Would it be, like, Europeans?