In my life I have found two things of priceless worth - learning and loving. Nothing else - not fame, not power, not achievement for its own sake - can possible have the same lasting value. For when your life is over, if you can say 'I have learned' and 'I have loved,' you will also be able to say 'I have been happy.

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

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.

Sometimes when I'm in a bookstore or library, I am overwhelmed by all the things that I do not know. Then I am seized by a powerful desire to read all the books, one by one.

Creationism, perhaps the most pernicious of the intellectual perversions now afflicting the American public.

The time was fast approaching when Earth, like all mothers, must say farewell to her children.

Deep beneath the surface of the Sun, enormous forces were gathering. At any moment, the energies of a million hydrogen bombs might burst forth in the awesome explosion.... Climbing at millions of miles per hour, an invisible fireball many times the size of Earth would leap from the Sun and head out across space.