The problem is that many people operate on the assumption that NASA should go to Congress every year with hat in hand and justify it every year. Well, I see it as the greatest economic driver that there ever was. Economic drivers don't need justification.

The press still thinks [global warming] is controversial. So they find the 1% of the scientists and put them up as if they're 50% of the research results. You in the public would have no idea that this is basically a done deal and that we're on to other problems, because the journalists are trying to give it a 50/50 story. It's not a 50/50 story. It's not. Period.

As a scientist, I want to go to Mars and back to asteroids and the Moon because I'm a scientist. But I can tell you, I'm not so naive a scientist to think that the nation might not have geopolitical reasons for going into space.

In just one year, the expenditure of of the U.S.'s military budget is equivalent to the entire 50-year running budget of NASA combined.

One of my great laments is that education today seems to have... be less about passion and more about process, more about tactic or technique.

Lots of people think, well, we're humans; we're the most intelligent and accomplished species; we're in charge. Bacteria may have a different outlook: more bacteria live and work in one linear centimeter of your lower colon than all the humans who have ever lived. That's what's going on in your digestive tract right now. Are we in charge, or are we simply hosts for bacteria? It all depends on your outlook.