It must be wonderful to be seventeen, and to know everything.

There were some things that only time could cure. Evil men could be destroyed, but nothing could be done with good men who were deluded.

Even if we never reach the stars by our own efforts, in the millions of years that lie ahead it is almost certain that the stars will come to us. Isolationism is neither a practical policy on the national or cosmic scale. And when the first contact with the outer universe is made, one would like to think that Mankind played an active and not merely a passive role-that we were the discoverers, not the discovered.

The moment when one first meets a great work of art has an impact that can never again be recaptured.

One theory which can no longer be taken very seriously is that UFOs are interstellar spaceships.

The dinosaurs disappeared because they could not adapt to their changing environment. We shall disappear if we cannot adapt to an environment that now contains spaceships, computers - and thermonuclear weapons.

Belief in God is apparently a psychological artifact of mammalian reproduction.