If you find life on Europa [Jupiter's moon], like, what would you call it? Would it be, like, Europeans?

We should not be ashamed of not having answers to all questions yet... I'm perfectly happy staring somebody in the face saying, 'I don't know yet, and we've got top people working on it.' The moment you feel compelled to provide an answer, then you're doing the same thing that the religious community does: providing answers to every possible question.

On some issues, I'm a staunch Conservative — like curtailing greenhouse gas emissions so that we can Conserve the environment.

Once you've got the makings of a star, gravity draws leftover gas and dust into a giant swirling disk. The dust continues to stick together, clumping into rocky asteroids, which eventually become orbiting rocky planets. And voila: a solar system!

A successful day for me is when I teach people something. They become enlightened by an idea and learn how to think about it, so that later on when someone says, "Tell me about x, y, z," they don't have to say, "I know this because Tyson told me." No, they'll say, "Here's why it's true because I know and understand it."

I don't like trying to influence politicians, who are themselves representative of huge numbers of people. As an educator, I'd rather enlighten the people and educate the people and let they be the ones who put the pressure on their elected officials.

The number of people in the world engaged in this search for catastrophic impactors totals one or two dozen. How long into the future are you willing to protect Homo sapiens on Earth? Before you answer that question, take a detour to Arizona's Meteor Crater during your next vacation.