We have also arranged things so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in our faces.

Whatever the reason you're on Mars, I'm glad you're there, and I wish I was with you.

I believe that the extraordinary should be pursued. But extraordinary claims require extraordinary evidence.

There are many instances in science, where those closest to the intricacies of the subject have a more highly developed sense of its intractability than those at some remove. On the other hand, those at too great a distance may, I am well aware, mistake ignorance for perspective.

You mustn't think of the Universe as a wilderness. It hasn't been that for billions of years," he said. "Think of it more as... ..cultivated.

There are in fact 100 billion galaxies, each of which contain something like a 100 billion stars. Think of how many stars, and planets, and kinds of life there may be in this vast and awesome universe.

Ours is the first generation that has grown up with science-fiction ideas.