I don't think there is such a thing as as a real prophet. You can never predict the future. We know why now, of course; chaos theory, which I got very interested in, shows you can never predict the future.

The realisation that our small planet is only one of many worlds gives mankind the perspective it needs to realise sooner that our own world belongs to all its creatures.

We seldom stop to think that we are still creatures of the sea, able to leave it only because, from birth to death, we wear the water-filled space suits of our skins.

We have to abandon the idea that schooling is something restricted to youth. How can it be, in a world where half the things a man knows at 20 are no longer true at 40 - and half the things he knows at 40 hadn't been discovered when he was 20?

You can't have it both ways. You can't have both free will and a benevolent higher power who protects you from yourself.

There is no reason to assume that the universe has the slightest interest in intelligence—or even in life. Both may be random accidental by-products of its operations like the beautiful patterns on a butterfly's wings. The insect would fly just as well without them.

Mars is the next frontier, what the Wild West was, what America was 500 years ago. It's time to strike out anew....Mars is where the action is for the next thousand years....The characteristic of human nature, and perhaps our simian branch of the family, is curiosity and exploration. When we stop doing that, we won't be humans anymore. I've seen far more in my lifetime than I ever dreamed. Many of our problems on Earth can only be solved by space technology....The next step is in space. It's inevitable.