Monday, May 17, 2010

Exploring a zoo of sounds

kw: book reviews, nonfiction, physics, particle physics, string theory

Many people have seen one or both (1951 & 2008) versions of the science fiction classic movie The Day the Earth Stood Still, based on a 1940 story, "Farewell to the Master" by Harry Bates. In the 1951 movie, Klaatu is assassinated, and the robot Gort temporarily resurrects him by means not specified (I haven't seen the 2008 remake). In the 1940 story, the robot is named Gnut, and the resurrection technique involves sound. Much of the story's plot concerns finding the best sound recordings of Klaatu's voice and a high-fidelity tape player, so that Gnut can use the least details of the sound to restore his Master to life, at least for a bit.

I've just finished reading The Little Book of String Theory by Steven S. Gubser, and just as I finished, I recognized the frustrated feeling I've always had when reading about strings, superstrings, and how they are supposed to lead to a theory that explains "everything"…except that we don't have any experiments yet that verify any predictions made by any of the many, many string theories (there are a lot of them), and it is actually close to impossible to use any of the theories to predict anything that can be tested!

Since Dr. Gubser's book is composed of a long series of analogies, let's analogize from my first paragraph. The frustrated feeling I get is akin to being led through a zoo blindfolded, and trying to infer what the creatures look like by the sounds they make. I view the well-populated madhouse of string theories as attempts by many, many means to restore Klaatu from the sound of his voice ("Klaatu" being just one kind of string, or brane, or whatever else).

I must give the author credit. His task is nearly insurmountable, to produce a popular book that explains string theory so as to produce some kind of "understanding" in a lay audience. I am hardly a layman, and I found it difficult. Yet, he did show me a thing or two. I'll mention one point that came through most easily:

I bridle at the thought of rolled-up dimensions. It turns out they do have their uses. One is to determine the duality of electric charge. A particle on a tiny (millions of times tinier than an atom) circular dimension, if it traverses it in one direction, can be a + charge, and in the other direction, a - charge. Since there are only two directions one may turn, there are only two kinds of charge, + and - .

After that, I began to wonder how quark colors were constrained, since there are three. The ensuing discussion of chromodynamics mentioned eight color "motions" (or "connections"?), but I never got clear how this leads to three quark colors.

Let's be clear, I am a failed physicist. In 1970, frustrated with the total emphasis on particle physics at my university, I changed majors to Geology. I needed a subject I could walk up to and hit with a hammer. (Now, I am very good at calculus, but there are levels of math to which particle physics ascends that had me floundering. I had 'way too much math for a Geology degree, but they forgave me and gave it to me anyway, in 1972.)

Fortunately, for those who have good skills at "getting" analogies, this book is the most readable account of string theory we are likely to see. You may not understand S-theory and D-branes and so forth after reading it, but they'll probably be a tad more familiar at least. Now, if they'd just say, "You smack this particle into that one, a few zillion times, and you'll have a blob of Z-stuff you can hit with a hammer," they'll have me.

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