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

In whatever you choose to do, do it because it's hard, not because it's easy. Math and physics and astrophysics are hard. For every hard thing you accomplish, fewer other people are out there doing the same thing as you. That's what doing something hard means. And in the limit of this, everyone beats a path to your door because you're the only one around who understands the impossible concept or who solves the unsolvable problem.

There's no tradition of scientists knocking down the Sunday school door, telling the preacher, That might not necessarily be true. That's never happened. There're no scientists picketing outside of churches.

Science is like an inoculation against charlatans who would have you believe whatever it is they tell you.

When everyone agrees to a single solution and a single plan, there's nothing more efficient in the world than an efficient democracy.

The history of exploration across nations and across time is not one where nations said, 'Let's explore because it's fun.' It was, 'Let's explore so that we can claim lands for our country, so that we can open up new trade routes; let's explore so we can become more powerful.'

Lots of people think, well, we're humans; we're the most intelligent and accomplished species; we're in charge. Bacteria may have a different outlook: more bacteria live and work in one linear centimeter of your lower colon than all the humans who have ever lived. That's what's going on in your digestive tract right now. Are we in charge, or are we simply hosts for bacteria? It all depends on your outlook.