Just before I said I wanted to be an astronomer I said I wanted to be a baseball player. I was quite athletic at the time, probably because I was bigger than other kids, and if you're bigger than other kids and you're 11 you win everything.

For me, I am driven by two main philosophies, know more today about the world than I knew yesterday. And along the way, lessen the suffering of others. You'd be surprised how far that gets you.

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.

Practically every food you buy in a store for consumption by humans is genetically modified food. There are no wild, seedless watermelons. There’s no wild cows.

As areas of knowledge grow, so too do the perimeters of ignorance.

Space only becomes ordinary when the frontier is no longer being breached.

The Venus transit is not a spectacle the way a total solar eclipse is a spectacle.