Astronomers have made the very public claim that they know the age of the universe pretty accurately: 13.7 billion years old. But how exactly do they know how old the universe is? David Weintraub answers this question in his accessible and detailed book How Old Is the Universe?
Astronomers, he explains, did not simply decide one day that 13.7 billion years sounded reasonable; they do not simply believe that the universe came to exist at one special moment 13.7 billion years ago. Rather, they have come to recognize and agree that this is the answer, because many independent lines of inquiry and evidence all yielded this same answer. What is this evidence? This one compelling, fundamental, and deceptively simple question deserves a thorough answer—an answer that requires knowledge of a great swathe of modern astronomy.
In answering the central question of his book, Weintraub discusses the many phenomena, concepts, and principles at the heart of modern astronomy and cosmology, including black holes, dark matter and dark energy, and the accelerating universe. By challenging readers not to simply accept astronomers’ answer to this fundamental question, but rather to understand the answer, he reveals how various areas of astrophysical research fit together and support each other, how evidence drawn from all of these areas of research allows the astronomical community to answer deep questions about the physical nature of our universe, how science and scientists work, and how—when astronomers say that the age of the universe is 13.7 billion years—the answer rests on solid foundations, built one stone at a time from painstakingly gathered evidence.
Owen Gingerich calls How Old Is the Universe? “a splendid merger of science history and cutting-edge astronomy.” It’s this blend of history and up-to-the-minute science, along with Weintraub’s insights into the nuts and bolts of scientific discovery, that makes the book so unique and fascinating, a true delight by an expert researcher and distinguished teacher of astronomy.
Weintraub is also the author of another Princeton University Press book: Is Pluto a Planet?: A Historical Journey through the Solar System
You can watch a video of Weintraub lecturing on how astronomers have discovered the age of the universe here.