When scientifically investigating the natural world, the only thing worse than a blind believer is a seeing denier.

The greatest teachers are the ones that turn a B student into an A student, or a failing student into a B student.

Like no other science, astrophysics cross-pollinate s the expertise of chemists, biologists, geologists and physicists, all to discover the past, present, and future of the cosmos-and our humble place within it.

Perhaps these ancient observatories like Stonehenge perennially impress modern people because modern people have no idea how the Sun, Moon, or stars move. We are too busy watching evening television to care what's going on in the sky.

We're quite happy with our Big Bang description of cosmic origins. But actually, the Big Bang accounts for what happened only after the beginning. The beginning itself, and especially what happened before, remains the biggest mystery of all.

I'd bet almost anything that life from another planet, if formed independently from life on Earth, would be more different from all species of Earth life than any two species of Earth life are from each other.

Anyone who has wrestled knows that it's the hardest thing in the world to do. Anyone who says something else is the hardest thing has never wrestled. That's what I have found. ... You don't wrestle because it's easy, you wrestle because it's hard. I don't do astrophysics because it's easy, I do it because it's hard. And I juxtapose the two in my mind, body, and soul all the time.