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Book Review: The Universe in the Rearview Mirror: How Hidden Symmetries Shape Reality

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I originally found this book while searching for a reasonably good summary of Noether’s Theorem, which has fascinated me for a few years. Strictly speaking, the subject of this book is not Noether’s Theorem exactly, but rather the role of symmetries in governing the laws of the universe, writ large. (Noether’s Theorem, approximately, states that every symmetry in the laws of physics yields a conserved quantity; for example, energy is conserved due to time symmetry.) The goal of the book seems to be to discuss the role of symmetry in physics, at a rather casual or informal level. Those who know a little physics, but not a lot, should feel more or less at home.

I think the goal was met maybe… two-thirds of the time. Especially in the early parts of the book, the discussion of anti-matter symmetry and so forth, was quite lucid and fascinating. Unfortunately, as we progressed into unification theories and categorization of sub-atomic particles, I was more and more lost. By the time we got around to discussing the classic experiments of quantum mechanics - which I recognized in the text despite the author’s best efforts - I thought that the text rushed through the material at hand, and relied more and more on the reader’s having already understood the background material. It made the discussion on spin feel rather… dizzying.

As regards Noether’s theorem, I really wish that more attention had been paid to it. There’s a good deal of background about the discoveries which paved the way for the theorem, about Noether’s life, and so on. But there’s very little explanation as to how the theorem itself was proved, or how it is that a given symmetry (such as time symmetry) yields another conserved quantity (energy). That is a failing of the book, though I suppose I have only myself to blame for not having picked up a book more specifically dedicated to the subject I wanted to learn, in the first place.

Though the discussion was rushed, I did enjoy learning about the various unification theories and sub-atomic particles that the book introduces. And I think the book reveals, and to some degree explains, a whole category of subjects which had previously been complete mysteries to me. So I appreciated that, and hope to read more about those subjects, some day.