Writings on physics

My articles

Though I am no longer working in theoretical physics, I maintain an interest in the subject-- in a way it's more fun than it was, since I can spend more time thinking about things that are not necessarily publishable or cutting-edge. Here are some expository articles that I've written, some adapted from Usenet posts and some written originally for the Web.

• Gravity: How it pulls on things. A slightly unusual take on the subject. The math is on a separate page for people who want to see it.
• Why is the sky blue? An explanation that contains no equations, yet is fairly detailed. The details are linked from the main page so that you can read as much or as little as you like.
• Seeing Haidinger's brushes: You may be able to detect the polarization of light with the unaided eye.
• Milne cosmology: Why I keep talking about it. In which an obsolete cosmological theory reveals lasting insights into the nature of an expanding universe.
• My opinions on the interpretation of quantum mechanics.
• A rambling letter I wrote about weak interactions and quarks.
• Where does the Boltzmann factor come from? (Contains some calculus.)

Physics links

• The Physics FAQ started out as the Frequently Asked Questions list for the Usenet group sci.physics. Now it's an extensive Web archive of answers to common physics questions. There are several mirror sites available from there, and links to many other online physics resources. I contributed parts of the sections on black holes and virtual particles.
• John Baez is a researcher in quantum gravity, and a fellow sci.physics.research moderator. His Web site has a fun and enlightening collection of expository articles on mathematical physics and other subjects (such as viruses and the Voynich manuscript).
• Greg Egan is my favorite currently working science-fiction author. He is also an avid explainer of mathematical and physical principles. His huge personal Web site has several complete stories for online reading, and also has a large collection of articles on math and physics, including the ideas used in some of his stories. The site is illustrated with an extraordinary collection of animations in the form of Java applets.
• Ned Wright's Cosmology Tutorial has amazingly clear, yet not oversimplified, explanations of what is really meant by the Big Bang and the expanding universe, illustrated with many ingenious diagrams.
• If you're wondering what a black hole would look like, take a look at this page of computer-generated movies of trips to black holes and neutron stars. It depicts the bizarre optical effects of extremely strong gravity. The site also has extensive explanations of the science behind the visuals.