Experimental evidence is the final arbiter of right and wrong.

No matter how hard you try to teach your cat general relativity, you're going to fail.

I think it's too fast to say that all sci-fi ultimately winds up having some place in science. On the other hand, imaginative minds working outside of science as storytellers certainly have come upon ideas that, with the passing decades, have either materialized of come close to materializing.

The pinpoints of starlight we see with the naked eye are photons that have been streaming toward us for a few years or a few thousand.

The real question is whether all your pondering and analyses will convince you that life is worth living. That's what it all comes down to.

My best teachers were not the ones who knew all the answers, but those who were deeply excited by questions they couldn't answer.

The main challenge that television presents is that I have a tendency to say things with a great deal of precision and accuracy. Often a description of that sort, which will work in a book because people can read it slowly - they can turn the pages back and so on - doesn't really work on TV because it interrupts the flow of the moving image.