We went to the moon using just Newton's laws of motion and gravity. Newtonian dynamics we call it. So then we find out, "Well, this works because there's certain regimes we've never tested it in." Had we done so, we would show that it didn't work: For example, at very high speeds, very high gravity, Newton's laws fail. They just fail. You need Einstein's laws of motion and gravity. Those would be his special theory of relativity and general theory of relativity. Now you invoke those and it works.

As important as the civil rights movement was, I think what will rise to the top is that we left Earth in that time.

My popularity does not derive from me pandering to people. People came to me. I don't tell anyone to follow me on Twitter. I don't tell people to like my Facebook page. I don't tell people to fill the venue. I'm offered to people, and then people come.

FM signals and those of broadcast television...travel out to space at the speed of light. Any eavesdropping alien civilization will know all about our TV programs (probably a bad thing), will hear all our FM music (probably a good thing), and know nothing of the politics of AM talk-show hosts (probably a safe thing).

When we went to the moon and realized that the Soviet Union had no realistic plans of getting to the moon, then we stopped going to the moon.

One should not be too distracted by definitions. Ideas transcend definitions.

If you're interested in something, that's all that matters. You'll spend more time doing it, that than anything else, and possibly more time doing it than anybody else.