J. Brit. Astron. Assoc., 107, 3, 1997, p. 148
University of Hertfordshire Press, 1997. ISBN 0-900458-79-8 (hbk), 0-900458-66-6 (pbk). Pp 197, £29.95/£14.95.)
reviewed by Karen Holland
Redshift is the first of a series of books entitled 'Building Blocks of Astronomy', and is completely devoted to the redshift phenomenon. This initial book comprises five chapters. The opening chapter explains the current understanding of the nature of light. The following three chapters give details of the currently, widely accepted causes of redshift. Doppler shift is considered, together with the way in which the doppler shift can be used to measure quantities such as galactic rotation, and the effect that it has on spectral lines. The section on gravitational redshift is concerned with the shift that light suffers when it is in an accelerating frame of reference, such as a gravitational field. An excellent example of this occurrence is given by describing how a US global positioning satellite must take the effects of both special and general relativity into account, when transmitting its data down to earth. And of course, a chapter on gravitational redshift would not be complete without mentioning black holes!
Cosmological redshift is a more difficult concept, in which the stretching of the space-time continuum is responsible for the redshift, but the author succeeds in elucidating this effect in his usual clear manner. The most fascinating chapter is undoubtedly the last, which debates unconventional interpretations of redshift (such as the 'tired light' theory) and also discusses many of the puzzling anomalies that exist.
The author, Dr Stuart Clark, is a research astronomer at the University of Hertfordshire. Anyone who has been fortunate enough to hear him lecture, will know that he has the rare ability to explain technically difficult concepts in simple language, that can be widely understood. This book has that same inimitable style, presenting the most challenging of theories in a beautifully lucid way.
Whilst Redshift is of an excellent level for amateur astronomers, it is also suitable for undergraduate reading and more seriously interested amateurs, due to the inclusion of separate, shaded theory boxes. These boxes work very well, as comprehension of the main text is not dependent upon an understanding of the mathematics,as in many texts. The theory boxes do make possible a greater level of understanding, for those who wish to use them. I struggled to find worthwhile criticisms of this book; there are some typographical errors throughout, but these do not detract from the subject matter. I would have preferred to see some diagrams in the early section describing the speed of light experiments, as I felt that diagrams would have better shown the experimental setup, than many words. However, these are minute points, and do not alter the fact that I thoroughly enjoyed reading the book and feel that it is essential reading. Having learnt about the various types of redshift, and the problems that astronomers face today in attempting to explain the anomalies, I was left wanting to know much, much more!
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