Society's emissions of carbon dioxide may or may not turn out to have something significant to do with global warming-the jury is still out.

If not for me, the H-bomb would have been developed in Russia first. In the U.S., we'd now be speaking Russian.

In the history of physics, there have been three great revolutions in thought that first seemed absurd yet proved to be true. The first proposed that the earth, instead of being stationary, was moving around at a great and variable speed in a universe that is much bigger than it appears to our immediate perception. That proposal, I believe, was first made by Aristarchos two millenia ago ... Remarkably enough, the name Aristarchos in Greek means best beginning.

I am guilty of the great crime of optimism.

My experience has been in a short 77 years that in the end when you fight for a desperate cause and have good reasons to fight, you usually win.

Today's science is tomorrow's technology.

If there ever was a misnomer, it is "exact science." Science has always been full of mistakes. The present day is no exception. And our mistakes are good mistakes; they require a genius to correct. Of course, we do not see our own mistakes.