May 11, 2017


Universal: A Guide to the Cosmos. By Brian Cox & Jeff Forshaw. Da Capo. $35.

     If you are wondering not only how the universe works but also why it works the way it does and not some other way, Universal: A Guide to the Cosmos is your kind of book. It is also physics professors’ kind of book: Brian Cox is a professor of particle physics and Jeff Forshaw is a professor of theoretical physics, both at the University of Manchester in England. Clearly, Cox and Forshaw spend their academic time with their heads way up in the clouds – more accurately, way up above the clouds. But they obviously come down to Earth periodically, if only to provide mere non-mathematically-inclined mortals with lucid and fascinating explanations of how things are and why they are that way. The “why that way?” notion is central to the book, with Cox and Forshaw explaining that an important element of cosmic science involves determining the same measurement by different means. Thus, an estimate of the sun’s age on the basis of how nuclear fusion works and how much heat reaches Earth gives about the same result for the age of the solar system (4.6 billion years) as an estimate of Earth’s age based on radioactive decay in planetary rocks. Casting doubt on any single measurement is relatively easy, Cox and Forshaw explain, but “it is usually extremely difficult to argue for a radical change in one area without making large parts of the whole interlinked edifice inconsistent.”

     The “edifice” here is science itself, and scientific inquiry. Universal is as much about the scientific method and the way scientists explore the cosmos as it is about intriguing specifics such as the Big Bang, supernovas, and dark matter. One thing Cox and Forshaw do exceptionally well here is to start by applying the scientific method to matters close to home and then gradually (and without too much higher mathematics) extend inquiry farther and farther out, into more and more complex and outré regions. Thus, the how-old-is-Earth question appears early in the book and leads Cox and Forshaw into well-paced, understandable discussions of plate tectonics and radioisotope dating, with everything they present involving observation, collection of evidence, and the application of logic to reach conclusions that can then be further tested using, ideally, different  methodologies. The authors’ quotation of Richard Feynman at one point is a wonderful kernel of explanation. Feynman said that the search for a new law of nature starts with a guess, then a computation of the consequences of the guess to see what would happen if the guess is correct – and then a comparison of the computation with nature “to see if it works. If it disagrees with experiment, it is wrong. In that simple statement is the key to science. It does not make any difference how beautiful your guess is, it does not make any difference how smart you are, who made the guess, or what his name is – if it disagrees with experiment, it is wrong.”

     This is a marvelous encapsulation that Cox and Forshaw have clearly taken to heart. Readers will be amazed at how easy it can be for anyone to test some important scientific hypotheses – for instance, an experiment to show the largest size an atom can be requires only cooking oil, a paper clip, a ruler and a bowl of water. Furthermore, entirely mundane matters are shown in Universal to be the foundation of extremely complex forms of observation and calculation. Take parallax, which is crucial to determining astronomical distances. Cox and Forshaw start by showing how it can be used to calculate the length of your own arm by holding a finger in front of you: the left and right eye see things differently, so by closing one and then the other, you can figure out the arm’s length based on how the apparent position of the finger changes. One of the many simple but elegant illustrations here shows how exactly the same procedure can be used to find the distance from Earth to Neptune, with your eyes being replaced for diagram purposes by the Earth in two different orbital positions and with Neptune representing the finger. It is this sort of clarity-through-extension that makes Universal so eminently readable and so marvelously informative. Colorful photos help enliven the book and enhance the explanations as well.

     What permeates this book is not only knowledge but also enthusiasm, and that is a source of much of the strength of Universal. Cox and Forshaw manage to deal with questions as huge as how much the universe weighs and what happened before the Big Bang (if that question even has any meaning) – without resorting to extreme complexities of calculation (the stuff that they surely use in their own everyday professorial lives) and without distorting the science they are explaining. They end up being near-perfect advocates both for the scientific method and for training top scientific minds to communicate with mere nonscientific mortals with tremendous insight and clarity – and without ever making non-scientists feel they are being talked down to, or that the tremendous difficulties of cutting-edge experimentation and analysis are being “dumbed down” to such a point that they no longer reflect how scientists think and how they test their thoughts for real-world (and real-universe) accuracy.

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