I think Newton would be the greatest scientist who ever lived.

When I get bored, or get stuck on an equation, I like to go ice skating, but it makes you forget your problem. Then you can tackle the problem with a fresh new insight. Einstein liked to play the violin to relax. Every physicist likes to have a past time. Mine is ice skating.

In the future, I can imagine that we will genetically modify ourselves using the genes that have doubled our life span since we were chimpanzees.

A hydrogen bomb, for me, was puny compared to the Big Bang - the creation of the universe. That's what I really wanted to work on - the nature of the universe itself, and that's what I do for a living.

I realized very early in life what my abilities and limitations were, and foreign languages was definitely one of my limitations. With strenuous effort, I just barely passed my French class at Harvard so I could graduate.

Scientists are embarrassed by science fiction; they want to distance themselves as much as possible. ... I think there's nothing to be ashamed of [and that] we should take science fiction seriously.

Global warming is controversial, of course, but the controversy is mainly over whether human activity is driving it.