August 11th, 2007

Books!

Big Math ... Weird Science ...

Yes, I'd read some reviews of Leonard Susskind's The Cosmic Landscape: String Theory and the Illusion of Intelligent Design before I picked it up, and was wondering about how I'd like it. These were generally positive, but with caveats ... however, a good friend highly recommended it, so I got a copy and sorted it into the reading rotation. My over-all take on this is "it's not as good as it could have been" ... but failed in ways that are perfectly understandable.

Frankly, Susskind started to "lose" me about 2/3rds of the way through this, not through disinterest, mind you, but in my being able to retain and contextify the info he was expounding. Given that I read (comparably to most readers) a lot of physics, and especially "cosmological" stuff like this, the fact that I was getting lost in this is rather telling. He does a great job up front in the book discussing QED, QCD, Feynman diagrams, Planck limits, the Cosmological Constant, and various spatial geometries, all leading up to the "Landscape" concept. However, at some point in there the explanations started to fade a bit and there would end up with lines like this:

"... branes annihilated one another and rearranged, fluxes shifted, and the sizes and shapes of several hundred moduli changed ..."
Ouch. Again, I've read a lot of stuff in this genre, and a substantial part of the latter part of this book was "new" to me ... which, admittedly, is likely to be the cause of much of my head-scratching. At several points I'd wished that I was in the classroom so I could have raised a hand to get clarification e.g. "Prof. Susskind, if there's a quark at one end of a string and an antiquark at the other, wouldn't there be a temporal frame when they'd cancel each other out?" (given that the anti particles can be described as regular particles moving backwards in time).

I suspect that, were I in that classroom, my hand would be up frequently, asking for clarification on stuff like fluxes moving through the holes in toroidal geometries, the whole concept of strings terminating in D-branes (which can't help to infect one with a Cypress Hill "earworm"), and lovely things like the Calabi Yau Manifold (pictured here), which are serious challenges to wrap one's mind around!

The whole thrust of the book is, of course, to place the Anthropic Principle (which basically says that the Universe is the way it is because if it was otherwise we would not be here to observe it) in a mathematically rigorous context which would serve as a bulwark against the "intelligent design" mob. Admittedly, there are things in the way the Universe is set up that are highly unlikely, but without them being right around that particular value, life as we know it would never have arose (the key of these, within the book, is the Cosmological Constant which is, for the first 119 decimal places, exactly zero, and only hitting a value, 1, at the 120th position, giving a value of 10-120, which, in effect, becomes the "odds" of a Universe having us around to look at it). Now, the "Landscape" is not a place (as opposed to the Megaverse), but a mathematical description of "all possible Universes" in which there are "valleys" (pockets of stability) which detail the specific moduli of charge, spin, field strength, etc., etc., etc., including stuff like how big the Cosmological Constant will be. Now, 10-120 is a very small number, but according to Susskind's model, the Landscape encompasses 10500 "valleys", and 10500 is a nearly inconceivably large number (to put this in context, the current understanding of the radius of the observable Universe is 4.4 x 1026 meters, and the size of the "Planck Length", the smallest theoretical measure of space, is 1.6 x 10-35 meter, making the entire universe only something like 1050 Planck Lengths end-to-end ... the number of "valleys" is still 10450 times as many as that!). Needless to say, in a "Landscape" of that size, there are plenty of opportunities for a "life-friendly" Universe to arise ... and, yes, in the Megaverse there are nearly endless numbers of Universes arising, disappearing, expanding, contracting, and hosting curious apes like ourselves.

Anyway, with the caveats noted, I enjoyed the challenge of The Cosmic Landscape, although I'm disappointed in myself that I didn't "get" all the details (in my defense, I will note that I have not "formally" studied any math past pre-calc in 11th grade, so I'm doing pretty well when I'm getting the gist of stuff like this, and am not going to "beat myself up" for not following the likes of this!). As is usually the case on recent releases (this came out in 2005), it is both available at retail, and is not at "give away" prices via the new/used vendors ... although you can get a "new" copy of the hardback (with shipping) from those guys for just slightly less than Amazon is selling the paperback (pre-shipping). Hey, if you like stretching your brain (not "brane") out a bit with advanced math and hard-to-visualize physics theories, this might be the book for you!


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