You can make a stack high enough to reach the moon and back, and only then will you have used your 100 billion hamburgers. This is terrifying news to cows.

UV is bad for molecules because its high energy breaks the bonds between a molecule's constituent atoms. That's why UV is bad for you, too: it's always best to avoid things that decompose the molecules of your flesh.

If Mars formed life, then life on Earth could have been seeded by life on Mars, making every life form on Earth descended from Martians.

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.

I as an astrophysicist, see the universe, feel the universe, smell the universe every day. Every day. And for people to say, I'm cool, I'm right here, it's all I need.

Somehow it's O.K. for people to chuckle about not being good at math. Yet if I said, 'I never learned to read,' they'd say I was an illiterate dolt.

If NASA were advancing a space frontier there would be challenges you've never seen before. You have to be creative and you have to patent some new idea. You get to Mars...well, how do we get the water from the soil? I gotta invent a new device that will do that. And the carbon dioxide in the atmosphere, how can we use that? Can we breathe the oxygen from the carbon dioxide?