We are living in a world in which all wars are wars of defense.

There's life all over this universe, but the only life in the solar system is on earth, and in the whole universe we are the only men.

Our challenge is to give what account we can of what becomes of life in the solar system, this corner of the universe that is our home; and, most of all, what becomes of men-all men, of all nations, colors, and creeds. This has become one world, a world for all men. It is only such a world that can now offer us life, and the chance to go on.

I can conceive of no nightmare so terrifying as establishing communication with a so-called superior (or, if you wish, advanced) technology in outer space.

We have to get rid of those nuclear weapons.

We are living in a world in which all wars are wars of defense.

A physicist is an atom's way of knowing about atoms.