I wonder if, in fact, we have been observed by aliens and upon close examination of human conduct and human behavior they have concluded that there is no sign of intelligent life on Earth.

Only when creative people take ownership of cosmic discovery will society accept science as the cultural activity that it is.

I don't want people to say, 'Something is true because Tyson says it is true.' That's not critical thinking.

I have thoughts every day that are themselves tweets.

With no gravitational force to work against, your body not only doesn't need the same amount of muscle and bone, it starts breaking them down. As on Earth, so in space: use it or lose it. And exercise may not solve the problem.

Whether or not you can become great at something, you can always become better.

I'm often asked whether I believe in Global Warming. I now just reply with the question: "Do you believe in Gravity?"