We living things are a late outgrowth of the metabolism of our galaxy. The carbon that enters into our composition was cooked in a remote past in a dying star. The waters of ancient seas set the pattern of ions in our blood. The ancient atmospheres moulded our metabolism.

A scientist should be the happiest of men. Not that science isn't serious; but as everyone knows, being serious is one way of being happy, just as being gay is one way of being unhappy.

As you lecture, you keep watching the faces, and information keeps coming back to you all the time.

A scientist lives with all reality. There is nothing better. To know reality is to accept it, and eventually to love it.

The great questions are those an intelligent child asks and, getting no answers, stops asking.

The only use for an atomic bomb is to keep somebody else from using one. It can give us no protection - only the doubtful satisfaction of retaliation...

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.