Robots are important also. If I don my pure-scientist hat, I would say just send robots; I'll stay down here and get the data. But nobody's ever given a parade for a robot. Nobody's ever named a high school after a robot. So when I don my public-educator hat, I have to recognize the elements of exploration that excite people. It's not only the discoveries and the beautiful photos that come down from the heavens; it's the vicarious participation in discovery itself.

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?

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.

Artificial selection turned the wolf into the shepherd, and the wild grasses into wheat and corn. In fact, almost every plant and animal that we eat today was bred from a wild, less edible ancestor. If artificial selection can work such profound changes in only ten or fifteen thousand years, what can natural selection do operating over billions of years? The answer is all the beauty and diversity of life.

Space enthusiasts are the most susceptible demographic to delusion that I have ever seen.

Follow the evidence wherever it leads, and question everything.

One thing in life is for certain, the more profoundly baffled you have been in your life, the more open your mind becomes to new ideas.