The universe for me was other planets and other star systems and other galaxies. I enjoyed tracking it, but it had no specific influence on my ambitions for that reason. It wasn't really far enough away from Earth to matter to me.

95, 96 percent of all that drives the universe has no known origin.

One of the greatest features of science is that it doesn't matter where you were born, and it doesn't matter what the belief systems of your parents might have been: If you perform the same experiment that someone else did, at a different time and place, you'll get the same result.

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

Astronauts are the only kind of celebrity I know who can have a line of people waiting for their autograph, even if the line of people does not know in advance the astronaut's name.

When you're enlightened, you don't have to reference other people, because you yourself are enlightened. And that's a better Earth. People can make more informed decisions politically, culturally, personally.

Newton came up with Newton's laws of motion and gravity. They worked. They were working.