The best educators are the ones that inspire their students. That inspiration comes from a passion that teachers have for the subject they're teaching. Most commonly, that person spent their lives studying that subject, and they bring an infectious enthusiasm to the audience.

If your ego starts out, "I am important, I am big, I am special," you're in for some disappointments when you look around at what we've discovered about the universe. No, you're not big. No, you're not. You're small in time and in space. And you have this frail vessel called the human body that's limited on Earth.

So not enough people in this world, I think, carry a cosmic perspective with them. It could be life-changing.

Darwin's theory of evolution is a framework by which we understand the diversity of life on Earth. But there is no equation sitting there in Darwin's 'Origin of Species' that you apply and say, 'What is this species going to look like in 100 years or 1,000 years?' Biology isn't there yet with that kind of predictive precision.

People think about life from day-to-day rather than thinking about life as something that invents a new kind of tomorrow.

George Bush, within a week of this [the 9/11 attacks], in a speech, attempting to distinguish US from the Muslim fundamentalists, said Our God is the God who named the stars. The problem is: two-thirds of all stars that have names, have Arabic names. I don't think he knew this. That would confound the point that he was making.

The first colony on Mars is not going to be built by a private company. How are you going to make money? You're not.