For all our conceits about being the center of the universe, we live in a routine planet of a humdrum star stuck away in an obscure corner ... on an unexceptional galaxy which is one of about 100 billion galaxies. ... That is the fundamental fact of the universe we inhabit, and it is very good for us to understand that.

For a long time the human instinct to understand was thwarted by facile religious explanations.

Science is a way to call the bluff of those who only pretend to knowledge. It is a bulwark against mysticism, against superstition, against religion misapplied to where it has no business being.

But, Jefferson worried that the people - and the argument goes back to Thucydides and Aristotle - are easily misled. He also stressed, passionately and repeatedly, that it was essential for the people to understand the risks and benefits of government, to educate themselves, and to involve themselves in the political process. Without that, he said, the wolves will take over.

I don't know the answer. Maybe no one knows. Maybe when you grow up, you'll be the first to find out.

By looking far out into space we are also looking far back into time, back toward the horizon of the universe, back toward the epoch of the Big Bang.

I believe that the extraordinary should be pursued. But extraordinary claims require extraordinary evidence.