When he was a boy growing up in the Bronx area of New York, Neil deGrasse Tyson couldn't see more than a few stars from his rooftop because of the bright city lights. Then he went to the Hayden Planetarium at New York's American Museum of Natural History and saw thousands of twinkling stars. It changed his life. He walked dogs to earn the money for his first telescope and went on to study at Harvard and Columbia universities.

Now, the boy born in October 1958 -- Tyson notes that he and NASA (the National Aeronautics and Space Administration) were "born" in the same week -- runs the Hayden Planetarium. He's an expert on the Milky Way, the galaxy that includes Earth, the sun and some 300 billion other stars as well as a lot of gas and stardust. He studies galaxies millions of light-years away. He's co-author of the book "Origins: Fourteen Billion Years of Cosmic Evolution" and the energetic host of the NOVA miniseries "Origins," which talks about how the universe began and how it became a place where life exists. The show airs on PBS Tuesday and Wednesday from 8 to 10 p.m.

Bridget Byrne asked Tyson some questions.

What do you say when someone asks, "What's an astrophysicist?"

I say I study the objects and things that go on in the universe and I give a short list -- planets, stars, black holes, big bang, and also the search for life in the universe.

Do you think kids today are savvy about space?

They see science-fiction movies, so they have some working vocabulary about the cosmos, more than we often give them credit for. So even if that working vocabulary is a little warped, because it comes from the entertainment section, it's still an important first starting point for a conversation.

What was it that grabbed your imagination when you first went to the Hayden Planetarium when you were a kid?

Not only the total darkness [of the sky] but also the number of stars up there. I was sure it was a hoax because it was nothing like the night sky I'd seen from the Bronx. . . . It wasn't just wallpaper; it was a place to dream about what it might be like to visit.

Was it easy to learn what you needed to learn to become an astrophysicist?

The language of the universe is mathematics . . . but my love of the subject was so deep and so strong that all that just became part of the journey. So many people have a bad first experience with math because they don't know why they are doing it, but if you have any curiosity about how the world works and communicates back to us, then it's easier to have a curiosity about math.

For you, what's the big question about the universe that remains unanswered?

[It's a] question about whether we can find evidence of life somewhere other than Earth. I think we have a chance of answering that question, at least in the next 10 years. I think that's the number one question kids, and adults, are curious about.

And what do you think the answer might be?

Oh, I'm pretty sure it's out there. . . . But when I say we are not likely to be alone, this is a very different statement from saying that we have been visited by intelligent aliens!

Astrophysicist Neil deGrasse Tyson studies things that go on in the universe, including planets, stars and black holes.