If you decide to become a dancer on Broadway, never say who your favorite dance partner is, because members of the media will presume you never want to dance with anybody else.

Anybody who grew up with the space program is a fan of science fiction.

Evolution is one of the most powerful and important ideas ever developed in the history of science. Every question it raises leads to new answers, new discoveries, and new smarter questions. The science of evolution is as expansive as nature itself. It is also the most meaningful creation story that humans have ever found.

When we see the shadow on our images, are we seeing the time 11 minutes ago on Mars? Or are we seeing the time on Mars as observed from Earth now? It's like time travel problems in science fiction. When is now; when was then?

One of the drawbacks of English is you can't spell things by hearing them.

Television isn't inherently good or bad. You go to a bookstore, there are how many thousands of books, but how many of those do you want? Five? Television's the same way. If you're going to show people stuff, television is the way to go. Words and pictures show things.

Not wasting any water bottles is good. Not leaving the lights on is good. Turning the thermostat down in the winter, up in the summer, is good. But the best thing any of us in the developed world, especially in the United States, can be doing is talking about it.