Book Review: Cosmic Evolution

Cosmic Evolution: The Rise of Complexity in Nature by Eric Chaisson.

Given the second law of thermodynamics, that entropy or disorder is always increasing in the universe, how did complexity arise in the form of galaxies, planets, life, and Boeing 747s arise? That is the question that Cosmic Evolution attempts to answer, with the added bonus of quantitative analysis. In simple summary, the expansion of the universe and the pull of gravity allows for energy gradients to emerge, and then systems that, by chance, take advantage of these gradients have a survival advantage and then all of power of natural selection hones them and their subsequent generation into higher and higher complexity. Thus is biological evolution generalized to cosmic evolution, and life defined simply as something more complex than inanimate matter.

How does one put the quantitative sword to complexity? Chaisson uses a metric he calls energy rate density, or energy per time per mass (he uses the CGS system which has some uncommon units like ergs and dynes. I’ve heard they are still common in astronomy [Chaisson is an astrophysicist] but it would be nice to see the values normalized to the SI system. It’s not hugely important, as long as you’re consistent, but I would have been more comfortable with the measure being in J/s/kg rather than erg/s/g. For the uninitiated, an erg is equal to 100 nJ). For a summarize view of the book and the analytical method used, here’s a paper written by Chaisson on the methodology.

Near the end of the book Chaisson takes a turn for the grandiose, identifying cosmic evolution as a new structure for speaking about events in the universe and talking about a transition from the Matter Era to the Life Era. He also goes to great lengths it seems to not piss off biologists who might be threatened by physics encroaching on their domain, which is both funny and stupid. Interdisciplinary science should be the norm rather than some recent movement in the sciences, since the fracturing of Nature into different domains of research is a fairly recent human thing.

Boiled down to its core, Cosmic Evolution is an essay on how energy rate density can be a widely-employed measure of complexity, and it use shows that complexity has been rising over the history of the universe and this is still consistent with the second law of thermodynamics (since complexity is a local phenomenon whereas entropy increase is global). Seems like a potentially lucrative avenue of research to me.

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