Only realistic flight schedules should be proposed, schedules that have a reasonable chance of being met. If in this way the government would not support them, then so be it. NASA owes it to the citizens from whom it asks support to be frank, honest, and informative.

Few people realize the number of things that are possible.

There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time ... On the other hand, I think I can safely say that nobody understands quantum mechanics.

Just as a poet often has license from the rules of grammar and pronunciation, we should like to ask for 'physicists' license from the rules of mathematics in order to express what we wish to say in as simple a manner as possible.

Don't worry about anything. Go out and have a good time.

The electron is a theory we use; it is so useful in understanding the way nature works that we can almost call it real.

We are very lucky to be living in an age in which we are still making discoveries. It is like the discovery of America-you only discover it once. The age in which we live is the age in which we are discovering the fundamental laws of nature, and that day will never come again. It is very exciting, it is marvelous, but this excitement will have to go.