As my old professor Carl Sagan said so often, 'When you’re in love, you want to tell the world.’ And I base my beliefs on the information and the process that we call science. It fills me with joy to make discoveries every day of things I’ve never seen before. It fills me with joy to know that we can pursue these answers. It is an astonishing thing that we are — you and I are one of the ways the universe knows itself.

If you meet somebody who says he or she has never dreamed of flying, I don't believe you. I mean, they're lying.

I'll admit that the discovery of evolution is humbling, but it is also empowering. It transforms our relationship to the life around us. Instead of being outsiders watching the natural world go by, we are insiders. We are part of the process; we are the exquisite result of billions of years of natural research and development.

The philosophy of science is inherent in the process. This is to say, you think critically, you draw a conclusion based on evidence, but we all pursue discovery based on our observations. That's where science starts.

There are just two people entitled to refer to themselves as "we"; one is the editor and the other is the fellow with a tapeworm.

If NASA is to reach beyond the Moon and someday reach Mars, it must be relieved of the burden of launching people and cargo to low earth orbit. To do that, we must invest more in commercial spaceflight.

I feel that I've often pointed out that there are countless aspects of life and nature that scientists and scientific thinkers cannot explain. Why the universe is accelerating in its expansion and what came before the Big Bang serve as compelling examples. The process of science provides a way to seek answers to those questions.