In whatever you choose to do, do it because it's hard, not because it's easy. Math and physics and astrophysics are hard. For every hard thing you accomplish, fewer other people are out there doing the same thing as you. That's what doing something hard means. And in the limit of this, everyone beats a path to your door because you're the only one around who understands the impossible concept or who solves the unsolvable problem.

I agree that we should go back to the moon and on to Mars. We should treat all objects in the solar system, including comets and asteroids, as exploration targets.

The very nature of science is discoveries, and the best of those discoveries are the ones you don't expect.

I want to encourage people to not think in terms of gifts, but think in terms of, wow. You work hard to succeed at that, because that's exactly what I do.

A state of negative energy means that you are essentially getting something for nothing.

My popularity does not derive from me pandering to people. People came to me. I don't tell anyone to follow me on Twitter. I don't tell people to like my Facebook page. I don't tell people to fill the venue. I'm offered to people, and then people come.

Curiosity is a self-driven motivation to explore and to learn. Learning is like... you know, you have to take your medicine. And that is what it has become. And that's unfortunate.