Gravity's century From Einstein's eclipse to images of black holes

Review by Choice Review

This slim volume bears a strong resemblance to a wolf in sheep's clothing. Its informal, readable style hides an enormous amount of physics and a fair share of history. About one-third of the material guides the reader through the thinking associated with the people and ideas that helped generate the theory of general relativity (GR). Einstein's gedankenexperiment, or thought experiment, emerges as key to catalyzing the equivalence principle, along with the idea of a curved space-time. The crucial Eddington observation, which made both scientific and journalistic history, paints a lively account of how fame came suddenly to Einstein. The GR tensor equation appears like magic, its function to illustrate that its solution is the foundation of modern cosmology. The text becomes increasingly dense in the discussions of quantum gravity and black holes, and there is a surprising amount of conjecture and detail in trying to explain the latest thinking relating quantum mechanics to GR. A collection of "Deeper Dive" inserts deals with issues that require more background or illustrations to enrich the storytelling, though the further reading section should be a useful supplement. This fine book should be in every library. Summing Up: Highly recommended. Upper-division undergraduates through faculty. --Kenneth L. Schick, emeritus, Union College (NY)

Copyright American Library Association, used with permission.

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Review by Publisher's Weekly Review

This gracefully written history of 20th-century gravity research from science writer Cowen shines a light on a key aspect of modern physics. As he explains, the current view of gravity began with a young Albert Einstein's curiosity about what a beam of light might look like. Cowen describes how Einstein eventually published the theory of general relativity in 1916, predicting how gravity would bend light. Proving this required photographing a solar eclipse in 1919 and seeing whether, as the theory predicted, the stars whose rays pass close to the sun would seem to shift position. When astronomer Arthur Eddington announced the photos showed that the sun's gravity did indeed bend light, Einstein became the world's first "science superstar." Cowen shows how successive generations of physicists have worked to understand gravity, exploring research that showed the universe was expanding (a conclusion Einstein initially resisted); observing this, and the rotation of galaxies, gave physicists their first clues about dark energy and dark matter. Other phenomena touched on include black holes, gravity waves, and even wormholes. Filled with vivid descriptions of cutting-edge work and the scientists behind it, Cowen's book is fascinating, both a learning experience and a pleasure to read. (May) © Copyright PWxyz, LLC. All rights reserved.

(c) Copyright PWxyz, LLC. All rights reserved

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Review by Kirkus Book Review

A brief history of the past 100 years of experimentation related to Einstein's theory of relativity, black holes, and more.The 100th anniversary of the 1919 eclipse photographs that showed the sun's gravity bending light waves and made Einstein a superstar has not gone unnoticed, so readers seeking a primer on relativity can choose from a rush of popular books, which includes this slim, earnest account. What's relative in relativity is motion, explains science writer Cowen. No matter how an observer moves, the laws of physics and speed of light never change. This sounds trivial, but the consequences are bizarre. In his 1905 discovery of special relativity, Einstein proved that time passes more slowly and objects grow heavier as they move faster. Time would stop and an object's weight become infinite at the speed of light, so this is an unreachable limit. Special relativity is easy; only high school math is required, but it only applies to steady motion. Einstein's general relativity theory of 1915 explained all motion, which includes acceleration and gravity. This formulation turned out to be wildly difficult. The math was so complicated that Einstein needed a mathematician friend's help. Cowen delivers a solid history of relativity's past 100 years. He works diligently and sometimes successfully to describe concepts such as curved space, black holes, gravitational waves, and dark energy. Most popular accounts admit that relativity explains the macroscopic universe but fails at the atomic level, which follows laws of the century's other great breakthrough in physics: quantum mechanics. Physicists are working hard to reconcile the two theories; none of many ingenious hypotheses have stood up, and Cowen's imaginative efforts to explain them are only partially successfulbut this is not an area where popular writers excel.A fine introduction to the basicsif not the complexitiesof relativity. Copyright Kirkus Reviews, used with permission.

Copyright (c) Kirkus Reviews, used with permission.

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