Gravity

February 13, 2012
As the most familiar physical force in the universe, gravity may not seem exciting, but British science writer Clegg (Armageddon Science) shows how this “omnipresent” force—which strengthens bones and muscles and binds together planets, stars, and galaxies—is anything but simple. The history of gravity theory begins with the ancient Greeks, who reasoned that “earthy” (as opposed to “airy”) objects had a kind of “natural heaviness” that made them “want to be at the center of the universe.” Centuries later, Galileo’s experiments with pendulums and rolling spheres revealed gravity as a force that controlled motion everywhere, but even Isaac Newton’s laws of motion failed to pierce the veil around this mysterious “action at a distance.” It took Einstein’s groundbreaking work on relativity theory to reveal how much gravity shapes the universe, warping space into an invisible world only revealed second-hand by the movement of masses and light. Clegg’s accessible presentation offers insight into everything from Aristotelian science to black holes and string theory as it reveals the complexities and surprises of a familiar force that continues to surprise scientists.

Starred review from March 1, 2012
Although by far the feeblest of the four universal forces, gravity is the only one we experience continuously. Every inquisitive person should read a book about it, preferably this one by prolific British science writer Clegg (How to Build a Time Machine: The Real Science of Time Travel, 2011, etc.). No revisionist, the author begins with the Greeks, who got it wrong. Believing that reason trumped observation (the senses could betray you), they thought deeply about gravity and concluded that heavy objects fell because they yearned to move toward the center of the universe (i.e., the Earth). Matters changed little for 2,000 years until Copernicus shifted the Earth away from the center, Galileo discovered the first equations of motion and Newton became the world's first scientific superstar by producing laws that described the movement of every object, from a falling rock to an orbiting planet, a dazzling accomplishment. However, for all his brilliance, Newton couldn't explain how gravity worked. The sun seemed to influence Earth magically across empty space. This made everyone uncomfortable, Newton included. After nearly 300 years during which scientists hypothesized a space filled with odd, invisible material that allowed one body to tug on another, Einstein solved the problem, explaining that any mass warps space-time in its vicinity. Moving through warped space changes the direction of nearby bodies, giving the impression that a force is acting. The downside (for readers) is that Einstein's version of gravity is more complicated than Newton's, but Clegg's skills never flag, and his account remains lucid and free of jargon, bad jokes and math phobia.

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June 15, 2012

Clegg (How To Build a Time Machine: The Real Science of Time Travel) acquaints readers with a very familiar force in their lives: gravity. To most people, gravity seems awfully powerful since it keeps them (and everything else) attached to Earth. As Clegg explains, however, gravity is, in fact, one of the weakest forces of nature, as he indicates in his subtitle. He takes readers on a delightful conversational tour of how gravity works and how humanity came to understand it. He brings to life household names like Newton and Einstein and the scientific circles in which they worked and lived. Explanations of giant stars and atomic nuclei demonstrate aspects of gravity most people don't think about, which makes this book all the more fascinating. VERDICT Lovers of science who are not well versed in its mechanics will find this book absorbing. Recommended.--Margaret Dominy, Drexel Univ. Lib., Philadelphia

Copyright 2012 Library Journal, LLC Used with permission.

April 1, 2012
Gravity is one of the most accepted laws of science. Drop an object and it falls to earth because of the attraction between the earth and the object. What alerts the earth and the object to act? Is there a sort of communication between them? Theoretical physicists have struggled to explain gravitational attraction over distance since Einstein posed his theories of special and general relativity. Quantum theory, string theory, M theory, and other theoretical inquiries have failed to solve the riddle. In his history of gravity from the Big Bang to the present, popular science author Clegg recounts international efforts to understand what is thought to be the weakest yet most essential force holding the universe together. Black holes, warps in space and time, and antimatter are featured in this wide-ranging account, which will be of interest to science students and readers of science fiction.(Reprinted with permission of Booklist, copyright 2012, American Library Association.)