The chunks of comet Shoemaker-Levy 9 were so large, and were moving so fast, that each hit Jupiter with at least the equivalent energy of the dinosaur-killing collision between Earth and an asteroid 65 million years ago. Whatever damage Jupiter sustained, one thing is for sure: it's got no dinosaurs left.

We live in the kind of society where, in almost all cases, hard work is rewarded.

The chances that your tombstone will read 'Killed by Asteroid' are about the same as they'd be for 'Killed in Airplane Crash.'

I want to create the airplane that flies in the rarified atmosphere of Mars. This is what galvanizes a generation to want to become scientists and engineers in the first place, not we need a scientist to develop a plane that's 20 percent more fuel-efficient than the one your parents flew.

Grab something off the shelf that's on the spaceship-an ashtray, it doesn't matter what. Because I can tell you, if they flew here from another galaxy, no matter what you've pulled off the shelf, it'll be unlike anything we have on Earth.

With automatic spell checkers running unleashed over what we compose, our era is that of correctly spelled typos.

Any time scientists disagree, it's because we have insufficient data. Then we can agree on what kind of data to get; we get the data; and the data solves the problem. Either I'm right, or you're right, or we're both wrong. And we move on. That kind of conflict resolution does not exist in politics or religion.