There are photons that have been traveling for 30,000 years, and I'm... snatching them from this journey and planting them into my digital detector. And then I started feeling bad for the photon, and I said maybe it wanted to continue but I got in its way. But then I said, no, those are probably happier photons than the one that slammed into the mountainside that will go unanalyzed and will not contribute to the depth of our understanding of the universe.

To the scientist, the universality of physical laws makes the cosmos a marvelously simple place. By comparison, human nature-the psychologist's domain-is infinitely more daunting.

I try to educate the public and let them make the decisions for themselves.

I'm not writing for myself. I'm writing as an educator, I'm writing to stimulate others.

If the purpose of the universe was to create humans then the cosmos was embarrassingly inefficient about it.

The most creative people are motivated by the grandest of problems that are presented before them.

We didn't go to the moon to explore or because it was in our DNA or because we're Americans. We went because we were at war and we felt a threat.