Saturday, November 22, 2014

The Universe in a Nutshell by Stephen Hawking (Book Review #110 of 2014)


The Universe in a Nutshell
I read this book followed by The Grand Design (back-to-back). Years ago, I read Hawking's Black Holes and Baby Universes, and it appears Hawking has changed his position on various things related to black holes and the Grand Unifying Theory since the 1980s, although he does not list them. How much of Hawkings remarks black holes does Hawking admit to be wrong on now? For that, I need to read Susskind's The Black Hole Wars. I have also read two of Brian Greene's works and was eager to compare. I found this book to be more accessible than Greene's works. Hawking's attempts at analogies describing time and space are brief and easier than Greene's drawn-out illustrations. Many of the negative reviews criticize the lack of depth, there are plenty of other works out there to choose from.

The reason the sky is dark at night is because not all of the light from the stars in the galaxy have reached us. This tells us that the universe must have been created at some finite point some time ago. Hawking details his own contributions to showing that the Big Bang happened. He discusses how it does no good to talk about what happened before time, which would require imaginary time. But Hawking believes scientists have a duty to investigate what happened before the Big Bang and what caused it. He has no patience for people like Carl Sagan who just weren't interested. Hawking explains Richard Feynman's concept of multiple histories. The concept of multiple histories still doesn't explain the cause of the big bang. While the crude form of the anthropic principle says the universe exists the way it is because we are here to see it, we can merge the principle with that of Feynman's multiple histories and supposedly explain why the universe is as we know it.

Determinism is obviously an issue in quantum physics. I would say that Hawking does not explain the multiple dimensions of M-theory very well; I would say he does a better job of that in The Grand Design (2010). To appeal to the sci-fi reader, Hawking has a rabbit rail on time travel. He explains how mathematically time travel is likely impossible, and would take an advanced civilization to figure out a way to do it without getting destroyed by radiation. He also has an odd divergence on human evolution and genetic engineering. While DNA doesn't seem to be evolving with new information, we're finding ways to engineer ourselves such that the human race will look dramatically different 400 years from now. We will have to do so to travel to the stars. This odd divergence on genetics is way outside his expertise and does not fit well in the book.

Hawking concludes with talk of a brane universe, and whether our universe is just a projected hologram. All of this is theoretical, which is a major problem for physicists. The scientific method, which Hawking holds favorably in The Grand Design, requires hypothesis testing. But Hawking ends the book by remarking that a particle collider larger than the universe would be required to test some of these theories. For more on these problems, and a large criticism of Hawking I plan to read Lee Smolin's The Trouble with Physics.

In all, good and accessible. 3.5 stars.

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