The idea of 10 dimensions might sound exciting, but they would cause real problems if you forget where you parked your car.

It's the gravity that shapes the large scale structure of the universe, even though it is the weakest of four categories of forces

What could define God, [is thinking of God] as the embodiment of the laws of nature. However, this is not what most people would think of that God. They made a human-like being with whom one can have a personal relationship. When you look at the vast size of the universe and how insignificant an accidental human life is in it, that seems most impossible.

We have made remarkable progress in the last hundred years, but if we want to continue, our future is in space.

A theory is a good theory if it satisfies two requirements: it must accurately describe a large class of observations on the basis of a model that contains only a few arbitrary elements, and it must make definite predictions about the results of future observations.

To confine our attention to terrestrial matters would be to limit the human spirit.

It matters that you don't just give up.