The right kind of greatness.

An old friend with close ties to the Chabot Space and Science Center in the Oakland hills send me an intriguing email message yesterday: A private showing was scheduled for this afternoon at Chabot's new Digital Planetarium. Entrance was restricted, but she could get me a pair of tickets if I wanted them. She thought I might, because Dr. Stephen Hawking would attend, and she knows what a groupie I am of Dr. Hawking's.

I snapped up the tickets -- I decided to take my daughter, who is approaching the age where girls stop thinking science is cool, and who needs some amazing experiences to keep her head right on the topic.

It was magical. The show in the planetarium spanned 10³⁰ meters, or 65 billion light years: from the surface of the Earth to the edge of the Universe. The journey was projected on the dome roof using a custom projection system built from a collection of ordinary PCs with graphics cards, reading a database of the positions of celestial objects managed on a clustered file system, with the whole thing driven in real-time from a console.

Doesn't sound very sexy, does it? Try it this way: Galaxies went zooming past our heads. We visualized the sphere, at about 75 light years out, marking the boundary of radio emissions from the Earth, and saw the stars in that sphere with planets around them. Is there intelligent life on those planets? Do they know about us from our radio smoke? If they do, I wonder what they wonder about us. We saw the large-scale structure of the Universe, both in the distribution of galaxies and in the cosmic microwave background radiation. Now that's sexy.

We saw Dr. Hawking arrive and leave. We were waiting in the lobby when he passed us on his way into the planetarium in his wheelchair. After the planetarium show, he offered just a few comments -- he had a talk tonight to give at the Paramount Theater in Oakland, so stayed for just a short while. His comments were interesting: If, he pointed out, the atmosphere were just a little cloudier, or if our eyesight were just a little poorer, we would never have divined the deep laws of physics, and might never have developed the science that marks our age so profoundly. Our understanding of physical law derives from our understanding of gravity, and it was Galileo and Kepler and Newton who conceived that understanding, from the motion of stars and planets in the night sky. It was an unusual insight: because we can only conceive of those things we can see, we need some kind of radio smoke ourselves, if we are to learn about the Universe we live in.

My daughter and I had a chance to talk about Dr. Hawking on our drive home. Some people are famous for being rich or pretty to look at, but they don't matter very much. Some, like sports stars, are famous for their skills, and those skills were developed by hard work. Whether they matter in the large sense or not, their dedication and effort demand respect. Dr. Hawking is famous better reasons. His is among the finest minds of our generation, exploring the Big Bang and black holes and the nature of time from evidence most of us can't see. His continued efforts in the face of the progress of ALS are an inspiration. It's impossible for me to imagine what it would be, to be locked inside a body that refused to act, with a mind that worked perfectly. That refusal to despair is the right kind of greatness.

After his remarks, Dr. Hawking left to prepare for his speech at the Paramount, and my daughter and I hit the hors d'oeuvres bar. Chabot opened two of their three telescopes -- the eight-inch refracting telescope (built in the 1880s!) and their 24-inch refractor. We saw Mars low on the horizon through a soupy atmosphere, and the moon higher in the sky and considerably sharper because of it.

We got our amazing experience.