Astrophysics in a Nutshell

Neil DeGrasse Tyson’s short (222 page) book on astrophysics is attractive in a 4.5 x 7.5- inch format (hardbound). Just looking at it you get the impression it would be easy and fun to read. If you have some science education and are familiar with modern cosmology and general relativity (and you should be if you count yourself as an educated person), the book is a breeze, written with style and wit.

Tyson starts at the beginning, with the Big Bang, and moves briskly on to the formation of stars and planets, and our solar system.  He talks about the mysteries of dark matter and dark energy, then tours through the periodic table of the elements, picking arbitrary favorites to comment on. Then he presents a history of astronomy, from the first visible light telescopes to spectroscopy and radio telescopes.  He describes the search for extra-solar earthlike planets, and then, looking from the outside-in, what aliens would see if they were searching the heavens for Earth. Would they find us?

If you saw Tyson’s television show, “Cosmos,” modeled after Carl Sagan’s 1980’s show of that name, you’ll recognize this tour. To cover the entire cosmos in a couple hundred pages and make it roughly hang together is a remarkable exercise in editing, all the more so because there is no math. It really is a good basic education in cosmology for someone who only has a few hours to give.

The content would be too much for a beginner new to these ideas,  nor will the book satisfy someone already familiar with modern astronomy and cosmology.  So who is it for?  I imagine it will appeal to those who read the science and technology sections in the popular press like the New York Times and The Economist, and someone who reads Science News and watches ‘Nova’ on PBS.  The book is indexed lightly for quick look-ups.

I do have some complaints. The content seems to be almost entirely excerpted from earlier Tyson books, especially Death by Black Hole, and Origins. If you’ve read those, there’s nothing new here. More seriously, the first chapter on the Big Bang is a meaningless word salad. For example, the very early universe, pinpoint small, ‘expanded’ rapidly. Well, what can ‘expanded’ possibly mean if gravity and therefore space and time had not yet been formed?  Nothing. It’s pure word soup.

Mathematically you can say that at T2, V2 was greater than V1 at T1. Those are variable names and they have numerical values and the equations they’re used in are internally consistent but they convey no commonsense meaning in ordinary language. Despite that, physicists of all stripes, from string theorists to quantum theorists and cosmologists seem immune to their own jabberwocky. I’d advise a naïve reader to skip the first chapter for that reason. It would take a lot more words than what Tyson offers here to make a coherent natural-language presentation of the Big Bang.

In the section on the development of astronomy, Tyson quickly (everything is quick in this book) moves from early visual observations to today’s large-scale radio telescopes, but though the book has a 2017 copyright, there is no mention of the new LIGO telescope that detects gravity waves and promises to open a new world of exploration.

When discussing what hypothetical aliens would have to do if they were to detect intelligent life on Earth, Tyson describes how well-hidden our planet is in the bright glare of our huge sun, and suggests that we would never be seen, but could be discovered in the radio spectrum because we give off a lot of radio waves. It’s an interesting section of the book but he fails to take into account the timescale. In cosmological time, humans have been capable of generating radio waves only for an immeasurably short flicker of an instant. Even if aliens had their scopes trained right on the planet, they would surely miss our shout.

Finally, the book ends with a longish reflection on the meaning of the cosmological observations discussed.  Many other reviewers seem to like that section, but I found it strained with manufactured sentimentality. Yes, space is big and we are small. Got that. But small as we are, we are ‘precious.’  What?  Precious to whom?  To ourselves, I guess.  Readers might skip the last chapter’s nonsense along with the first.

Despite some flaws, the book is excellent for the right reader.  It would make a perfect gift for any scientifically curious person, perhaps a special high-school or college student.

Tyson, Neil De Grasse (20117). Astrophysics for People in a Hurry. New York: W.W. Norton. 222 pp.

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