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.

You don't believe in organized religion, yet a major theme in so many of your works seems to be a quest for God.

At the present rate of progress, it is almost impossible to imagine any technical feat that cannot be achieved - if it can be achieved at all - within the next few hundred years.

Few artists thrive in solitude and nothing is more stimulating than the conflict of minds with similar interests.

Training was one thing, reality another.

When a distinguished but elderly scientist states that something is possible, he is almost certainly right. When he states that something is impossible, he is very probably wrong. Perhaps the adjective 'elderly' requires definition. In physics, mathematics, and astronautics it means over thirty; in the other disciplines, senile decay is sometimes postponed to the forties. There are, of course, glorious exceptions; but as every researcher just out of college knows, scientists of over fifty are good for nothing but board meetings, and should at all costs be kept out of the laboratory!

A man who grows that much hair,' critics were fond of saying, 'must have a lot to hide.