While the Copernican principle comes with no guarantees that it will forever guide us to cosmic truths, it's worked quite well so far: not only is Earth not in the center of the solar system, but the solar system is not in the center of the Milky Way galaxy, the Milky Way galaxy is not in the center of the universe, and it may come to pass that our universe is just one of many that comprise a multiverse. And in case you're one of those people who thinks that the edge may be a special place, we are not at the edge of anything either.

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.

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.

There was a transition going on - Baghdad being the intellectual capital of the world where major advances were made in agriculture and mathematics and engineering and medicine and astronomy, and then that all sort of collapsed. And I was trying to understand how such a intellectually fertile environment can lose its compass bearing. Because I think about the creative centers today - countries, or even regions. Will Silicon Valley always be as innovative? Will the United States be innovative, or will we become complacent?

As areas of knowledge grow, so too do the perimeters of ignorance.

The tenacity of life is mind-boggling. We keep finding it where no one thought it could be.

The miniaturization of electronics, which ultimately was driven by the marketplace, was started by NASA, because it costs money to get something into orbit. So you want to trim your electronics, miniaturize your electronics, miniaturize your satellites.