One of the reasons we're here, that we exist at all, is that Earth, cosmically speaking, is in a relatively peaceful place: orbiting our Sun in a near perfect circle.

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.

Science literacy is the artery through which the solutions of tomorrow's problems flow.

Those who see the cosmic perspective as a depressing outlook, they really need to reassess how they think about the world. Because when I look up in the universe, I know I'm small but I'm also big. I'm big because I'm connected to the universe and the universe is connected to me.

The dinosaurs never saw that asteroid coming. What's our excuse?

You get to say that the Earth is flat because we live in a country that guarantees your free speech. But it's not a country that guarantees that anything you say is correct.

You don't need to be a scientist to know Earth's age or that life evolved. You just need be one who embraces objective truths