The Cosmic Century: A History of Astrophysics and Cosmology

  • Malcolm Longair
Cambridge University Press: 2006. 565 pp. £35, $60 0521474361 | ISBN: 0-521-47436-1

John F. Kennedy once addressed what he called the “most extraordinary collection of talent, of human knowledge, that has ever been gathered at the White House, with the possible exception of when Thomas Jefferson dined alone”. After diving into Malcolm Longair's epochal The Cosmic Century, a history of astronomy and astrophysics, he is the one I would want to dine with if I wanted to learn about an unlimited range of material.

Longair's book is a complete reworking and major extension of a chapter he once wrote for a history book of twentieth-century physics. This background perhaps explains how such a knowledgeable astronomer was inveigled into spending the time needed to gain such a broad view. It's no surprise that the author of Alice and the Space Telescope (Johns Hopkins University Press, 1989) can write clearly and invitingly, but I had to sample deeply to verify that he did not give short shrift to such wide-ranging topics as the discovery of exoplanets, the use of helioseismology to analyse the inside of the Sun, and advances in supernova research brought about by observations of SN 1987A.

Different readers may want different treatment of the subjects, depending on their mathematical backgrounds. Longair's discussion of Einstein's general theory of relativity, for example, provides sets of equations that may scare off non-physicists. But most of his treatments are non-mathematical, and many are humanized with quotations. For example, Longair not only points out that Jocelyn Bell first recognized the signals we now know as pulsars, but describes how he was present when the Soviet astrophysicist Iosif Shklovsky told her, “Miss Bell, you have made the greatest astronomical discovery of the twentieth century” (at least as far as 1970, when the encounter took place). Those familiar with the history of the discussion over credit for the discovery may note that he gives Antony Hewish, Bell's supervisor who shared the 1974 Nobel prize for physics for his work on pulsars, an acknowledgement for reading the chapter from which this book sprang.

Longair also tells the story of an underground seminar (literally, given its location in the basement of the Leiden Observatory in the Netherlands) in 1944, at which Jan Oort asked a young H. C. van der Hust to calculate whether any spectral lines would be detectable in the radio part of the spectrum. Longair's discussion describes the result (a spectral line at 21 cm) and explains how it was used to map the quasi-spiral arms of the Milky Way. He then describes the subsequent detection of 125 different molecules in the interstellar matter, and explains how the unexpected relationships of their abundances led researchers to deduce how the molecules were formed.

The section on exoplanets — unfortunately only a subsection of the chapter on the interstellar medium — explains the importance of high-precision spectroscopy, and starts with the pulsar planets discovered by Aleksander Wolszczan and Dale Frail. Longair then discusses the first optical detections of exoplanets by Michel Mayor and Didier Queloz, and a chapter endnote directs readers to The Extrasolar Planets Encyclopaedia if they want to keep up-to-date. I think it would have been fair to also mention the extensive work in the field by Geoff Marcy and Paul Butler, and their encyclopaedic website at www.exoplanets.org.

Little of astrophysics and cosmology escapes the gaze of Longair, a former astronomer royal for Scotland who now heads the Cavendish Laboratory in Cambridge, UK. Readers, especially those already familiar with many of the topics, will enjoy his prose. Certainly all graduate students in the field should read this book. And anyone interested in the history of science would enjoy it as bedside reading if they were willing to skip the equations.