The greatest discoveries all start with the question "Why?"

I believe in just enriching the economy. And we're leaving so much on the table, 72 percent of the planet.

Almost a quarter of our planet is a single mountain range and we didn't enter it until after Neil Armstrong and Buzz Aldrin went to the moon. So we went to the moon, played golf up there, before we went to the largest feature on our own planet.

You don't go to Gettysburg with a shovel, you don't take belt buckles off the Arizona.

Most of the time you are growing up, people tell you what's wrong with you. Your coach tells you, your parents tell you, the teachers tell you when they grade you. I think that's very good in the early stages, because it helps you then develop skills. But at some point in your career, generally I think when you are in your teens, you look in a mirror and you have to say, despite all the bumps and warts, "I like that person I'm looking at, and let's just do our best."

Remember to always dream. More importantly, work hard to make those dreams come true and never give up.

Fifty percent of the United States of America is underneath the ocean. And we have better maps of Mars than those areas.