Many people feel small because they're small and the universe is big, but I feel big.

If you want a nation to have space exploration ambitions, you've got to send humans.

Everything we do understand about the universe - the periodic table of elements, Einstein's laws, Newton's laws, all of chemistry, all of biology - that's 4 percent of the universe. We got to the moon on the 4 percent we do understand. We landed on Mars on the 4 percent we do understand. So the day we crack the nut of the rest of that 95 percent... Oh my gosh.

In five billion years, the sun will expand and engulf our orbit as the charred ember that was once Earth vaporizes. Have a nice day

The good thing about science is that it's true whether or not you believe in it.

If you're interested in something, that's all that matters. You'll spend more time doing it, that than anything else, and possibly more time doing it than anybody else.

These are two different exercises. One of them is, "You don't know and I know, so just shut up and listen," and the other one is, you're curious and you're learning, and I have a way where you can learn this so you'll know it as well. And when you know it, and know why you know it, then you don't have to reference me ever again because you take ownership of the knowledge, and you can then share it with someone else.