If you look at Earth from space you see a dot, that's here. That's home. That's us. It underscores the responsibility to deal more kindly and compassionately with one another and to preserve and cherish that pale blue dot, the only home we've ever known.

The size and age of the Cosmos are beyond ordinary human understanding. Lost somewhere between immensity and eternity is our tiny planetary home.

When Kepler found his long-cherished belief did not agree with the most precise observation, he accepted the uncomfortable fact. He preferred the hard truth to his dearest illusions, that is the heart of science.

Not explaining science seems to me perverse. When you're in love, you want to tell the world.

That we can now think of no mechanism for astrology is relevant but unconvincing. No mechanism was known, for example, for continental drift when it was proposed by Wegener. Nevertheless, we see that Wegener was right, and those who objected on the grounds of unavailable mechanism were wrong.

We invest far off places with a certain romance... Long summers, mild winters, rich harvests, plentiful game; none of them lasts for ever. Your own life, or your bands, or even your species - might be owed to a restless few, drawn by a craving they can hardly articulate or understand, to undiscovered lands, and new worlds.

All civilizations become either spacefaring or extinct.