One of my fixed childhood memories is my father's library: a board attached tightly to the wall with not beautifully but carefully angled drywall screws. There were six books on the shelf.

One of them was Isaac Asimov's The Solar System and Back. I have it in my library now - or rather, I have some pages and a cover held together by an elastic band. The book is no longer in print. My father is no longer in print.

My sense of wonder about the universe may be genetic, or it could be that I just want to know what my father was so curious about. But I, too, have a library full of books that cause me to ponder the similarity between an atom and a solar system. And I understand why my father needed only five or six books. I read mine over and over, and each time I understand a tiny bit more about where we came from and where we're going.

I believe Jesus had a clue about the universe, but made the mistake of explaining it in parables. God's laws, my father used to say, are the laws of nature. What he was really saying, I think, is that stories of gods and miracles are shallow distractions from things that are true, and truly amazing.

The energy of anything - you, me, a stone, a blade of grass, a planet - is its mass times the speed of light squared. Imagine that.

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I have a sister, Kathy, who can't resist math questions. She would point out, correctly, that if the equation had any merit in the real world, she would have at least enough energy to clean her entire house in one go.