Cosmological Physics

  • John A. Peacock
Cambridge University Press: 1999. 694pp. £70, $85, (hbk); £24.95, $39.95 (pbk)

In the 1920s, a pair of discoveries — one observational and one theoretical — launched the modern era of cosmology. Hubble found his redshift distance relation, and Einstein's theory of general relativity was found to have either expanding or contracting solutions for a uniform, isotropic Universe.

By itself, either discovery would have been impressive. But the conjunction of a bold application of physical theory to the entire Universe and an observational fact was truly astonishing. There was plenty of immediate confusion, given the rather young Universe implied by Hubble's erroneous distance scale and a number of alternative physical models. More recently, a perhaps even deeper excitement has surrounded the application of new ideas in quantum-field theory and particle physics to the problems of the very early Universe and its relation to the existence of matter and structure. This new conjunction of physics and astrophysics offers tests of particle physics theory at energies far beyond any laboratory accelerator.

The intermingling of observational detail and fundamental theory has made cosmology an exceptionally rich, exciting and controversial science. Students in the field — whether observers or particle theorists — are expected to be acquainted with matters ranging from the Supernova Ia distance scale, Big Bang nucleosynthesis theory, scale-free quantum fluctuations during inflation, the galaxy two-point correlation function, particle theory candidates for the dark matter, and the star formation history of the Universe. Several general science books, conference proceedings and specialized monographs have addressed these issues. Peacock's Cosmological Physics ambitiously fills the void for introducing students with a strong undergraduate background in physics to the entire world of current physical cosmology. The majestic sweep of his discussion of this vast terrain is awesome, and is bound to capture the imagination of most students.

Cosmological Physics will appeal to the adventuresome, and may trouble those who like to see every detail of an argument spelled out. The avalanche of ideas rapidly, but not breathlessly, coaxes the reader straight into the excitement of the field. Peacock takes the view that an introduction to the physics of cosmology should not shield the reader from ideas and data whose significance is not yet clear. For instance, he includes brief sections on modified Newton dynamics and the anthropic principle. In spite of this, some of the observational details have already seen substantial changes in their interpretation, notably the redshift dependence of the star formation rate.

The result is an impressive overview of cosmology as a physical science. This abundance will communicate the widespread excitement of the subject as fundamental physics, and will inspire others to learn the details.