Any civilization that doesn't develop space travel dies.

It is clear that the nations of the world now can only rise and fall together. It is not a question of one nation winning at the expense of another. We must all help one another or all perish together.

Understanding is a kind of ecstasy

Modern science has been a voyage into the unknown, with a lesson in humility waiting at every stop. Many passengers would rather have stayed home.

There is perhaps no better a demonstration of the folly of human conceits than this distant image of our tiny world.

We are star stuff which has taken its destiny into its own hands. The loom of time and space works the most astonishing transformations of matter.

A celibate clergy is an especially good idea, because it tends to suppress any hereditary propensity toward fanaticism.