I've known from long ago that the universe was calling me. If you were one of those annoying adults that said, 'Oh, what are you gonna be when you grow up?' I would say, 'Astrophysicist .' And then they'd walk away real quickly.

There are two ways you can receive energy from your environment: One is molecules bumping against you. That's the air. The other is radiative energy. That's what you're feeling from the sun. When they say "Get out of the sun, out of the heat," the air is the same temperature; it's just you're exposed to sunlight.

People think about life from day-to-day rather than thinking about life as something that invents a new kind of tomorrow.

When your reasons for believing something are justified ad hoc, you are left susceptible to further discoveries undermining the rationale for that belief.

Any time scientists disagree, it's because we have insufficient data. Then we can agree on what kind of data to get; we get the data; and the data solves the problem. Either I'm right, or you're right, or we're both wrong. And we move on. That kind of conflict resolution does not exist in politics or religion.

In fact, I think it was the philosopher Hume who argued that it's far more likely that a miracle is a new physical phenomenon that we have yet to discover and have now discovered in that moment than it is a spiritual force coming down from God making something happen in front of you.

Asteroids have us in our sight. The dinosaurs didn't have a space program, so they're not here to talk about this problem. We are, and we have the power to do something about it. I don't want to be the embarrassment of the galaxy, to have had the power to deflect an asteroid, and then not, and end up going extinct.