Somewhere, something incredible is waiting to be known.

By exploring other worlds we safeguard this one. By itself, I think this fact more than justifies the money our species has spent in sending ships to other worlds. It is our fate to live during one of the most perilous and, at the same time, one of the most hopeful chapters in human history.

The near side of a galaxy is tens of thousands of light-years closer to us than the far side; thus we see the front as it was tens of thousands of years before the back. But typical events in galactic dynamics occupy tens of millions of years, so the error in thinking of an image of a galaxy as frozen in one moment of time is small.

My deeply held belief is that if a god of anything like the traditional sort exists, our curiosity and intelligence is provided by such a God. We would be unappreciative of that gift if we suppressed our passion to explore the universe and ourselves.

Our ancestors lived out of doors. They were as familiar with the night sky as most of us are with our favorite television programs.

If I finish a book a week, I will read only a few thousand books in my lifetime, about a tenth of a percent of the contents of the greatest libraries of our time. The trick is to know which books to read.

One of the great commandments of science is: 'Mistrust arguments from authority.'