On the day that we do discover that we are not alone, our society may begin to evolve and transform in some incredible and wondrous new ways.

Because men, compared to male chimps, have such relatively small testicles (large testicles indicate a species where many males mate, one after the other, with the same female), we might guess that promiscuous societies were uncommon in the immediate human past.

The secrets of evolution are death and time-the deaths of enormous numbers of lifeforms that were imperfectly adapted to the environment; and time for a long succession of small mutations.

We were wanderers from the beginning.

I would be very ashamed of my civilization if we did not try to find out if there is life in outer space.

What does it mean for a civilisation to be a million years old? We have had radio telescopes and spaceships for a few decades; our technical civilisation is a few hundred years old ... an advanced civilisation millions of years old is as much beyond us as we are beyond a bushbaby or a macaque

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.