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.

I never got into 'Star Wars.' Maybe because they made no attempt to portray real physics. At all.

Lots of people think, well, we're humans; we're the most intelligent and accomplished species; we're in charge. Bacteria may have a different outlook: more bacteria live and work in one linear centimeter of your lower colon than all the humans who have ever lived. That's what's going on in your digestive tract right now. Are we in charge, or are we simply hosts for bacteria? It all depends on your outlook.

The solar system should be viewed as our backyard, not as some sequence of destinations that we do one at a time.

You gotta be a good sport! So when I would lose, I would say, "That guy was better than I was; what do I have to do to be better next time?"

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!

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.