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

The limits of the possible can only be defined by going beyond them into the impossible.

Across the gulf of centuries, the blind smile of Homer is turned upon our age. Along the echoing corridors of time, the roar of the rockets merges now with the creak of the wind-taut rigging. For somewhere in the world today, still unconscious of his destiny, walks the boy who will be the first Odysseus of the Age of Space.

Much blood has also been spilled on the carpet in attempts to distinguish between science fiction and fantasy. I have suggested an operational definition: science fiction is something that COULD happen - but usually you wouldn't want it to. Fantasy is something that COULDN'T happen - though often you only wish that it could.

Finding intelligent life would encourage people and also of course the opportunity of learning a tremendous amount, but this is a danger. We might be so overwhelmed with knowledge and information, that we might be depressed or even become suicidal - because what's the point if they're thousands of years ahead of us? Why should we bother? - or become the ultimate couch potatoes.

There's a passage about 'rivers of molten rock that wound their way... until they cooled and lay like twisted dragon-shapes vomited from the tormented earth.' That's a perfect description: how did Tolkien know, a quarter century before anyone ever saw a picture of Io? Talk about Nature imitating Art.

The Shuttle is to space flight what Lindbergh was to commercial aviation.