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.

What are you doing? Why are you concerning yourself with the meaning of meaning?

Nothing is a thing: it's nothing. So I can imagine a place where there's not even nothing.

The most accessible field in science, from the point of view of language, is astrophysics. What do you call spots on the sun? Sunspots. Regions of space you fall into and you don’t come out of? Black holes. Big red stars? Red giants. So I take my fellow scientists to task. He’ll use his word, and if I understand it, I’ll say, “Oh, does that mean da-da-da-de-da?

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.

We didn't go to the moon to explore or because it was in our DNA or because we're Americans. We went because we were at war and we felt a threat.

One of the things that fascinates me most is when people are so charmed by the universe that it becomes part of their artistic output.