E=MC2

A readable history and explanation of the only physics equation that has taken on a life of its own in popular culture.

“Everyone knows that E=mc2 is really important, but they usually don’t know what it means, and that’s frustrating, because the equation is so short that you’d think it would be understandable,” Oxford science lecturer Bodanis (The Secret Family, 1997) confides in the preface. This paradox—that practically everyone can recite the formula, but hardly anyone understands it—spurred the author to write an accessible guide for nonscientists. His tone stays chatty and cheerfully enthusiastic through sketches of the various characters involved in the development of Einstein’s equation, technical explanations of each of its components, and discussions of the theoretical and practical applications. His “biography” includes lively if superficial portraits of an assortment of colorful scientists, including Antoine-Laurent Lavoisier (who established the concept of mass before coming to a nasty end in the French Revolution) and Lise Meitner (whose explorations of the mechanisms of matter led to the evolution of laboratory techniques for splitting atoms); unfortunately, the author tends to reduce the physicists’ specialized training and exceptional abilities to the kind of spunky rebelliousness familiar from Hollywood versions of scientific genius. The explications of the actual elements of the equation—energy, the equal sign, mass, celeritas, and the exponent—are just as entertaining, but they are also a little too glib (at least for anyone who floundered through high-school physics). There’s a vivid explanation of the properties of light, for example, but the function of celeritas (the figure representing the speed of light) as a conversion factor in the equation goes by too quickly to be illuminating, at least for a genuine science dunce. However, the account of the development of the atomic bomb makes clear the interchangeability of matter and energy, as well as providing a fast-paced, suspenseful tale.

Bodanis delivers on his promise to make the significance of Einstein’s formula at least somewhat understandable for general readers. (20 b&w illustrations, not seen)