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 kinds of comments that I get. One is, oh, you're such a natural up there, and the other one is, you're working hard up there. And the ones who say I'm working hard are teachers, they're the educators; they're the people who are the performers. It's a huge investment of my psycho-emotional energy to pull that off and to make it look smooth.

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!

You can't have people making decisions about the future of the world who are scientifically illiterate. That's a recipe for disaster. And I don't mean just whether a politician is scientifically literate, but people who vote politicians into office.

For all we know, the aliens have already done this and unwittingly concluded that there was no intelligent life on Earth. They would now be looking elsewhere. A more humbling possibility would be if aliens had become aware of the technologically proficient species that now inhabits Earth, yet they had drawn the same conclusion.

We went to the moon and discovered Earth.

I think that intelligence is such a narrow branch of the tree of life - this branch of primates we call humans. No other animal, by our definition, can be considered intelligent. So intelligence can't be all that important for survival, because there are so many animals that don't have what we call intelligence, and they're surviving just fine.