A LITTLE BOOK ABOUT THE BIG BANG

A concise examination of the origin of the universe.

Most readers find it difficult to imagine a universe that has existed forever, but it’s equally hard to imagine it popping out of nowhere 14 billion years ago. Rothman, a physicist and former editor at Scientific American, points out that until the early 20th century, astronomers believed that the heavens were vast and unchanging. Once they learned that the universe was expanding, some simply rewound the clock. This required a Big Bang, but without concrete evidence, other theorists proposed a steady-state universe in which galaxies simply appeared to fill the voids as others receded. This changed after 1965, when astronomers discovered cosmic microwave background radiation. The universe has a temperature. Since it’s expanding, it’s cooling, so it was hotter in the past when it was denser. This killed the steady-state theory, and countless provocative questions have followed, some of which seem embarrassing—e.g., “What came before the big bang?” One of Rothman’s advisers once told him, “If you ask a stupid question you may feel stupid. If you don’t ask a stupid question, you remain stupid.” Readers will not remain stupid after this book, but those curious about black holes, exploding stars, and extrasolar planets must look elsewhere because Rothman concentrates on the big picture, focusing on gravity, the force controlling the fate of the universe, and Einstein, the first to get gravity right. Einstein’s masterful theory of general relativity describes our universe on the large scale but requires quantum theory for behavior at the atomic scale, and the theory fails to explain what happened at the instant of the Big Bang or why ordinary matter makes up only 5% of the universe. Although illustrations are simple and equations absent, Rothman offers mostly clear explanations of complex concepts, including quantum gravity string theory and the nature of dark matter and energy.

Lucid and informative.