Speaking as just simply an American who cares about the economic health of our country, I see one of the surest ways to bring wealth and prosperity to the country is to innovate in science and technology.

Just before I said I wanted to be an astronomer I said I wanted to be a baseball player. I was quite athletic at the time, probably because I was bigger than other kids, and if you're bigger than other kids and you're 11 you win everything.

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.

You have the illusion of free will, but, in fact, that illusion comes about because you don't know the future. Because you are a prisoner of the present, forever locked in transition, between the past and the future.

The theory of evolution, like the theory of gravity, is a scientific fact.

It’s short-sighted to think ads won’t one day end up wherever humans are - even the moon.

One of the most significant events in our distant past is still perhaps the greatest mystery: the origins of life itself.