Where there's water on Earth, you find life as we know it. So if you find water somewhere else, it becomes a remarkable draw to look closer to see if life of any kind is there, even if it's bacterial, which would be extraordinary for the field of biology.

Who you are, where you've been and what you've done is all up here, captured and preserved in your memories. If you lost that - the story of your own origins - you'd lose your identity, your sense of self.

I have a multivolume history of the world from the 19th century that begins with Noah's flood as though it's as historical a fact as the rise and fall of Rome.

The greatest explorer of recent decades is not even human.

The most creative people are motivated by the grandest of problems that are presented before them.

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?

I as an astrophysicist, see the universe, feel the universe, smell the universe every day. Every day. And for people to say, I'm cool, I'm right here, it's all I need.