As a scientist, I want to go to Mars and back to asteroids and the Moon because I'm a scientist. But I can tell you, I'm not so naive a scientist to think that the nation might not have geopolitical reasons for going into space.

This fear factor, this war driver is a very strong one and it's been with the species ever since the beginning and it motivated the Great Wall of China. War can be aggressive or defensive, right? So it motivated the Great Wall of China. Our space program was reactive to Russia.

'Cause a musician, you can't tell me, "I've got this message I want share with the public," and it's three-and-a-half minutes long. That's not it. If your message is only three-and-a-half minutes long, then we got nothing else to talk about. Because life is more complex than three-and-a-half minutes.

I am not the most annoying person to bring to a movie 'cause I basically hold it in and write about it later or tweet about it. The most annoying people to bring to movies, I think we all agree, are those who read the book first.

There's no denying the public's appetite for cosmic discovery.

The StarTalks - while kids can watch them, they're actually targeted at adults. Because adults outnumber kids five to one, and adults vote, and adults wield resources, and adults are heads of agencies. So if we're going to affect policy, or affect attitudes, for me, the adults have always been the target population.

To assert that the universe has a purpose implies the universe has intent. And intent implies a desired outcome. But who would do the desiring? And what would a desired outcome be? That carbon-based life is inevitable? Or that sentient primates are life's neurological pinnacle? Are answers to these questions even possible without expressing a profound bias of human sentiment? Of course humans were not around to ask these questions for 99.9999% of cosmic history. So if the purpose of the universe was to create humans then the cosmos was embarrassingly inefficient about it.