On Gravity – A Brief Tour of a Weighty Subject by A. Zee, 192pp, (HB) $19.95 (US) £14.95 (UK) ISBN 9780691174389 (E-book ISBN9781400890309), Princeton University Press.
Gravity is probably the force we’re most familiar with in our daily lives. We learn very quickly that things fall down unless you hold them in place somehow – so far, so boring.
Yet gravity is also the force responsible for black holes and for gravitational waves, whose discovery literally rocked our world (albeit only by an incredibly tiny amount). On Gravity: A Brief Tour of a Weighty Subject is physics professor Anthony Zee’s attempt at explaining how we went from thinking of gravity as objects going home to searching for quantum gravity.
Since researchers first discovered gravitational waves, popular science books about gravity have been filling up bookshops. What makes this one different is its focus: rather than being aimed at complete beginners, Zee aimed this book at people who might have worked their way through the popular science books available but aren’t ready to tackle a graduate-level textbook. On Gravity isn’t shy about including equations, but these are clearly explained so that they add to readers’ understanding rather than frightening them away.
Chapters are extremely short, sometimes only two pages. Zee focuses on the concepts behind general relativity rather than its history and in doing so manages to cover some much-needed ground. For example, symmetry (broadly speaking, the idea that the laws of physics should be the same everywhere in the universe) is an important concept in physics, but often glossed over in the popular literature. However, the chapters are intended as summaries and can be a little confusing for readers without the required background.
Normally, the best parts of a book are the chapters in the main body. Here, the appendix and the notes are what really set On Gravity apart! Zee is a knowledgeable and witty man, and while he has to stick to the physics to keep the chapters brief, the notes are filled with asides about the lives and times of various physicists.
The appendix itself is a whistle-stop tour of curved spacetime. It requires basic calculus and is easily the most challenging section of the book, but Zee manages to explain advanced mathematical concepts very simply and discovering the mathematics behind curved spacetime is an incredibly rewarding experience.
On Gravity is definitely not a book for beginners, but readers who already know about general relativity and want to be challenged will find that challenge here.
