Einstein's theory, we know that it fails. In advance, we know it fails. So that a deeper understanding of nature is awaiting us.

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.

Today secular philosophers call that kind of divine invocation God of the gaps-which comes in handy, because there has never been a shortage of gaps in people's knowledge.

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.

The number of people in the world engaged in this search for catastrophic impactors totals one or two dozen. How long into the future are you willing to protect Homo sapiens on Earth? Before you answer that question, take a detour to Arizona's Meteor Crater during your next vacation.

Newton came up with Newton's laws of motion and gravity. They worked. They were working.

You can deceive yourself into thinking that America is a technological leader, but if you don't see what anyone else is doing you have no accurate assessment - you can't make an accurate assessment of where you fit and why. I consider our moving frontier in space as the anecdote to that downward trend.