I don't live life to be remembered for anything.

On some issues, I'm a staunch Conservative — like curtailing greenhouse gas emissions so that we can Conserve the environment.

I believe that the manned space program can engage the public by advancing the space frontier. Every next mission takes you farther out in space than you were before, either technologically or in terms of distance.

The limits on your enlightenment come not from the age you stopped going to school but from the age you stopped being curious.

What I’m saying is, when different experiments give you the same result, it is no longer subject to your opinion. That’s the good thing about science: It’s true whether or not you believe in it. That’s why it works.

One of the most significant events in our distant past is still perhaps the greatest mystery: the origins of life itself.

The value of the space program is beyond science, it's beyond military; it's a cultural shift in how we think of our place in the universe.