Typically, when you look for role models, you want someone who has your interests and came from the same background. Well, look how restricting that is. What people should do is take role models a la carte. If there's someone whose character you appreciated, you respect that trait.

The day that you stop looking - because you're content God did it - I don't need you in the lab. You're useless on the frontier of understanding the nature of the world.

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.

New generations of humans inherit the acquired discoveries of generations past, allowing cosmic insight to accumulate without limit. Each discovery of science therefore adds a rung to a ladder of knowledge whose end is not in sight because we are building the ladder as we go along. As far as I can tell, as we assemble and ascend this ladder, we will forever uncover the secrets of the universe - one by one.

If humans one day become extinct from a catastrophic collision, there would be no greater tragedy in the history of life in the universe. Not because we lacked the brain power to protect ourselves but because we lacked the foresight. The dominant species that replaces us in post-apocalyptic Earth just might wonder, as they gaze upon our mounted skeletons in their natural history museums, why large headed Homo sapiens fared no better than the proverbially peabrained dinosaurs.

What do you call those knobby things on doors that help you open them?

Give a kid a book, and you change the world. In a way, even the universe.