Darwin's cosmic legacy
Written: Oct 16 '00 (Updated Jun 17 '03)
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Product Rating:
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Pros: imaginative trip through cosmology
Cons: hey, it's physics. You have to pay attention.
The Bottom Line: Universes evolve. Now that's a concept.
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| JayAckroyd's Full Review: Lee Smolin - The Life of the Cosmos |
One of the great mysteries of our time is why the universe exists at all. In particular, there are some numbers in physics equations we observe in experiment, but have no theoretical underpinning. Take Planck's constant (1.05 X 10^ -27 grams-cm/sec). It is an empirically observed value that plays a key role in determining the size of quanta in sub-atomic events. There are lots of numbers like Planck's constant--the speed of light, the cosmological constant, the mass of the electron, and the strength of the strong force are other examples. These numbers are usually called parameters, because they could in principle take on a different value without changing the correctness of the equation.
That's a mouthful, I know. But here's the catch. As I said, the value of these parameters aren't determined by any equation. They just are. It turns out that if any of these couple dozen parameters are just a little bit different, the universe is very different. One way in which it almost always is very different is that there are no people. We need to live in a universe where there are a lot of novas, because novas create elements like carbon, which is what we're made of. The odds of the parameters being set to allow people, if they were set randomly, is one in 10^229, or some such absurd number. In the past, this has been seen as an argument for God--getting the dials turned exactly right to create a universe with people sounds like a god-like function.
Lee Smolin points out, in Life of the Cosmos that one way of characterizing the dial settings that permit life to exist at all are those settings that generate universes with lots of black holes. Universes that have their dials set for a few black holes are short-lived universes. It takes a long time to blow up enough stars to create enough carbon to make people out of, so you need a long-lived universe, which means you need a lot of black holes.
But this blithe tossing around of the idea of multiple universes is a little disconcerting. What mechanism can possibly drive multiple universes? Smolin suggests that it could be the case that universes are created by black holes. It is true that the description of the starting point of the big bang, a nearly infinitely dense point is the same as the description of a black hole. It is also true that if there were universes on the other side, they'd be invisible to us because we can't enter a black hole.
But the interesting wrinkle comes when Smolin suggests that there is a mechanism we're all familiar with that might serve to explain how this incredibly improbable universe came about--natural selection. Since universes with lots of black holes tend to create more universes, there is a tendency for universes with lots of black holes to gradually dominate the collection of universes.
Watching him get to this conclusion is a lot of fun, as he introduces modern cosmological concepts along the way. Smolin also presents the material in a down-to-earth manner, telling you something of his interesting life story.
Oh, and by the way, other cosmologists don't think this is such a crazy idea.
Recommended:
Yes
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Epinions.com ID:
JayAckroyd
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Member: Jay Ackroyd
Location: New York NY
Reviews written: 20
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