Let's create a World's Fair that captures everybody's visions of tomorrow together and let's celebrate that vision. Let's have articles on it with illustrators imagining how we'd be living differently.

Asteroids have us in our sight. The dinosaurs didn't have a space program, so they're not here to talk about this problem. We are, and we have the power to do something about it. I don't want to be the embarrassment of the galaxy, to have had the power to deflect an asteroid, and then not, and end up going extinct.

The past is another planet.

In just one year, the expenditure of of the U.S.'s military budget is equivalent to the entire 50-year running budget of NASA combined.

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.

You will never find scientists leading armies into battle. You just won’t. Especially not astrophysicists -we see the biggest picture there is. We understand how small we are in the cosmos. We understand how fragile and temporary our existence is here on Earth. We understand there are bigger problems we need to solve as a species than what God you pray to.

All tweets are tasty. Any tweet anybody writes is tasty. So, I try to have each tweet not simply be informative, but have some outlook, some perspective that you might not otherwise had.