Heart of Darkness: Unraveling the Mysteries of the Invisible Universe, Jeremiah P.Ostriker and SimonMitton, Princeton U. Press, 2013. $27.95 (299 pp.). ISBN 978-0-691-13430-7

Can anyone explain to a general audience how astronomers converged on such an astonishing story as the now-standard concordance model of cosmology, with its Big Bang and with large doses of dark matter and dark energy that only astronomers could “see” and most didn’t want? Will the audience believe what it is told? And can the story keep the attention of the professional physicist? The answers are yes, as evidenced by Heart of Darkness: Unraveling the Mysteries of the Invisible Universe by Jeremiah Ostriker and Simon Mitton. Ostriker, a theorist, is a leader in modern cosmology, and Mitton, a physicist-journalist, is an excellent storyteller as well.

The book’s introductory material includes an overview of Hipparchus and the methods of the Greek astronomers. It also traces the beginnings of modern astronomy and physics and briefly introduces Albert Einstein’s toolkit: quantum mechanics, special relativity, and general relativity; relevant calculations are banished to an appendix. Most of the introduction is conceptually very clear, one of the best versions I’ve seen.

The preliminaries are followed by a discussion of the discovery of the expanding universe—a history much more interesting and complex than is generally appreciated. For instance, the book mentions the race in 1912 between Vesto Slipher, with his 24-inch refractor, and William Campbell, with his 36-inch telescope. Both men knew that measuring the spectra of galaxies was important, even though it was not yet known that galaxies were very distant or that they contained stars. In 1915 Slipher showed that most galaxies had redshifts, and in 1927 Georges Lemaître predicted a linear relation between distance and velocity. So when we say that Edwin Hubble discovered the expanding universe, we’re simplifying a bit too much; I’m glad to see that this book gets it right.

Heart of Darkness also discusses the evidence for dark matter as seen by Fritz Zwicky in the 1930s, the fruitless hunt for the cosmic deceleration parameter, the history of Einstein’s cosmological constant, and some of the many ways astrophysicists now measure dark matter. And the text offers some delightful salvos against those who claim that the end of science is nigh or that scientists don’t change their minds until the “paradigm shifts.”

The book is less enchanting in its stories of the past decade. The writing is more technical, with too many self-citations by Ostriker. The general reader might not care who did what in modern theory, whereas the physicist will care about those details, since the participants are alive and well known today. The astonishingly precise and presumably accurate measurements and implications of the cosmic microwave background fluctuations do not get the detailed treatment needed. There are no diagrams to illustrate how telescopes work, how spectrometers work, or how cosmic microwave background radiation is measured.

As the project scientist and one of the three principal investigators for the Cosmic Background Explorer (COBE) satellite, and now senior project scientist for the James Webb Space Telescope, I am attuned to the how and why of measurements. I wish those questions had been addressed in this book, given that most of the recent progress in cosmology has come from improved technology, especially in space missions. With few exceptions, cosmological theory is driven by surprises in measurement, and most of those surprises are discovered with new equipment. For convincing proof of that, see Martin Harwit’s brilliant book, Cosmic Discovery: The Search, Scope, and Heritage of Astronomy (Basic Books, 1981).

The book also gets some of the details about COBE wrong; it misstates Earth’s age (it is 4.6, not 3.7, Gyr); and on page 207 it gives an incorrect calculation of escape velocity. Overall, though, Heart of Darkness is a cheerful and accessible introduction to some of the most fascinating topics in astronomy today. It presents the concepts clearly, tells the stories about the discoverers with remarkable detail, and explains the logic leading to the hypotheses of dark matter and dark energy. I would not hesitate to recommend it for both general readers and scientists.

John Mather is senior project scientist for the James Webb Space Telescope at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. He and George Smoot shared the 2006 Nobel Prize in Physics for their measurements of the cosmic microwave background radiation.