"The universe is a hostile place. It will kill you if you're not careful."

"I find that if you have a goal, that you're going to work toward it. And if you don't have a goal, you're going to wander around aimlessly."

"I'm not a guru. I'm just a guy who knows a lot about space."

"If you're scientifically illiterate, you're a danger to yourself and society."

"I'm not a vegetarian, but I do believe that we should be more mindful of where our food comes from, and how it's produced."