Neil Armstrong was no Christopher Columbus. In most respects, he was better. Unlike the famous fifteenth century seafarer, Armstrong knew where he landed. He also spent his time in public service, not in jail, and his passing was marked by world-wide encomiums. He ended his days as a celebrated explorer rather than a royal inconvenience.

The split between religion and science is relatively new. Isaac Newton, who first worked out the laws by which gravity held the planets and even the stars in their traces, was sufficiently impressed by the scale and regularity of the universe to ascribe it all to God.

If this is the only planet on which not only life, but intelligent life, has arisen, that would be very unusual.

[O]ne might ask why, in a galaxy of a few hundred billion stars, the aliens are so intent on coming to Earth at all. It would be as if every vertebrate in North America somehow felt drawn to a particular house in Peoria, Illinois. Are we really that interesting?

If you took all the sand from all the beaches, all the desserts, and all the oceans and called that the Universe, our whole solar system would be less than one grain of sand.

Like prospecting in the 19th century, reconnaissance of the asteroids would of necessity take place in an arena where trouble is likely and help is distant. Heroic stories of individual triumph and failure, set on landscapes never seen by humankind, are in the cards.

The number of habitable worlds in our galaxy is certainly in the tens of billions, minimum, and we haven't even talked about the moons. And the number of galaxies we can see, other than our own, is about 100 billion.