Principles of Cosmology and gravitation



ISBN: 0-521-29028-7

File Type: djvu

File Size:  1 MB

Language: English


Modem scientific cosmology is one of our grandest intellectual adventures. It is also physics, uninhibited, applied on the largest scale. Indeed, many people are first 'turned on' to physics by popular books or films about cosmology. What a pity, then, that the subject is rarely taught in universities. Perhaps this is because a suitable textbook is lacking. There are many advanced treatises for the specialist, and many elementary expositions for the lay reader, but at the undergraduate level there is a gap. This book is designed to fill that gap, and so promote teaching of cosmology in universities. The aim is to describe the universe as revealed by observation, and to present a theoretical framework powerful enough to enable important cosmological formulas to be derived and numerical calculations performed.

Any serious treatment must grasp the nettle of Einstein's general theory of relativity, because this gives the best description of the behavior of matter and light under the influence of gravity; it forms the basis of current 'standard cosmology', and is employed constantly in the interpretation of observations. Here we avoid an elaborate and formal discussion based on the tensor calculus. Of course it is necessary to introduce the general expression for the separation (or interval) between two events, and this involves the metric tensor of space-time. However, it is possible in the case of the highly symmetrical space-times of elementary general relativity and cosmology to determine the metric tensor by employing Gauss's formula for the curvature of an ordinary two-dimensional surface instead of using the general Einstein field equations. The curvature of a surface is a concept that makes no demands on the credulity of a student, so that this approach is a convenient way to introduce the geometrical interpretation of gravity.

A previous exposure to the ideas of special relativity is assumed, as is a knowledge of calculus, including partial differentiation. This book is, therefore, a suitable text for the final year of an undergraduate physics course. Experience shows that the material can be covered comfortably in twenty-four lectures. Problems of varying difficulty are included, together with solutions.

In writing this book I have used a great variety of sources, and it is impossible to acknowledge them all. The works I found most helpful are included in the bibliography, as recommended additional reading. I am most grateful to Dr P. G. Drazin, Dr M. S. Longair and Professor J. F. Nye for critically reading the manuscript and correcting a number of errors (they are, of course, not responsible for any that remain).

Finally, I would like to thank my students for their gentle responsiveness to this introduction of cosmology into their curriculum. It will not help them get a job, nor will it help them serve the military-industrial complex or increase the gross national product. But it will, I hope, contribute to the revival of the old idea that physics should be, above all, 'natural philosophy'.
Similar Books