Science has been effective at furthering our understanding of nature because the scientific ethos is based on three key principles: (1) follow the evidence wherever it leads; (2) if one has a theory, one needs to be willing to try to prove it wrong as much as one tries to prove that it is right; (3) the ultimate arbiter of truth is experiment, not the comfort one derives from one's a priori beliefs, nor the beauty or elegance one ascribes to one's theoretical models.

In 5 billion years, the expansion of the universe will have progressed to the point where all other galaxies will have receded beyond detection.

You couldn't be here if stars hadn't exploded, because the elements - the carbon, nitrogen, oxygen, iron, all the things that matter for evolution - weren't created at the beginning of time. They were created in the nuclear furnaces of stars, and the only way they could get into your body is if the stars were kind enough to explode. So, forget Jesus. The stars died so that you could be here today.

We now know that we are more insignificant than we ever imagined. If you get rid of everything we see, the universe is essentially the same. We constitute a 1 percent bit of pollution in a universe . . . we are completely irrelevant.

You shouldn't be afraid of science. Accepting the reality of nature makes life more exciting and even more precious.

Of course, supernatural acts are what miracles are all about. They are, after all, precisely those things that circumvent the laws of nature. A god who can create the laws of nature can presumably also circumvent them at will. Although why they would have been circumvented so liberally thousands of years ago, before the invention of modern communication instruments that could have recorded them, and not today, is still something to wonder about.

Aside from communications satellites, space is devoid of industry.