Friday, April 23, 2004

Today's Reading

Hopefully this will be a regular item. Anyway, after finishing up Adrian Goldsworthy's The Punic Wars (the Romans win, Carthage delenda), I went to postmodern physics: Brian Greene's new book, The Fabric of the Cosmos: Space, Time, and the Texture of Relativity.

I read Greene's earlier The Elegant Universe. The parts that I already understood (basic quantum mechanics, general relativity) were very, very well written. The parts that I didn't know (string theory, M-branes, 9 or 10 +1 dimensions) weren't as clear. This may not be Greene's fault. It's hard to describe 10 dimensional systems, especially when 6 or so of them are wound up in complicated snake-biting-its-own-tail toruses (torii?). I was also a bit put off by the fact that Greene implicitly assumes that string theory is the absolutely, positively correct way to merge quantum mechanics and general relativity, even though we can't solve all of the equations yet, so we don't know what the results are going to be.

Coincidentally, this week I heard a talk by Sir Roger Penrose. They have different takes on the basic problem of todays physics: Greene wants to save Quantum Mechanics by modifying General Relativity. Sir Roger wants to save General Relativity by modifying Quantum Mechanics, specifically the Copenhagen Interpretation.

Greene's version, string theory + supersymmetry, has certain verifyable features that should be tested soon. If it fails the test, Sir Roger's version might be looking good.