The Curvature of Spacetime: Newton, Einstein, and Gravitation (review)

Harald Fritzsch has produced a book intended to "contribute to the incorporation of Einstein's ideas into our more general culture, and not just into the expert's domain of knowledge" (Preface). Despite its reputation for incomprehensibility, relativity theory generated many beautifully simple ideas, even though they stretch the credulity of our intuitive understanding of nature.

Using the format of an imaginary three-way dialogue between Einstein, Newton and a fictional contemporary physicist called Adrian Haller, the book discusses gravitation according to the general theory of relativity. The dramatic tension in the debate lies between Newton's view of the universe in which time, space and matter are independent and absolute properties of nature and Einstein's view that these are each interdependent and relative properties of a universal spacetime continuum. The Haller character intervenes to update his companions on the latest data and theories from current physics research. Einstein tries to explain his ideas to a skeptical Newton using an array of thought experiments, logical arguments, intuitive insights and analogies, many of which are graphically illustrated in the book.

On many different levels this is a staggering read. First, the sheer scales involved in relativity theory, sub-atomic and astro-physics—both the micro- and the macroscopic—are unimaginable. We are dealing with measurements that are, at one extreme, billionths of billionths of a centimeter small and, at the other, trillions of miles long. There are immensities of heat, depths of coldness, magnitudes of energy, and speeds so colossal that one is left simply staring at numbers, trying to form some image that refuses to materialize. On another level, one is left in awe of the achievements of both Newton and Einstein and their capacities for perseverance and original thought. Finally, there is the semi-religious sense of one's own transient existence combined with the almost comforting sense of continuity with a universe that transcends life itself. It is little wonder that Einstein made such frequent reference to God, as the quotes included in this volume bear witness.

There have been many admirable attempts to bring Einstein's ideas to a wider public, and I am sure The Curvature of Spacetime makes a contribution to that process. It is by no means the easiest of such books to read, particularly for one with no scientific training and very little mathematical fluency. But I found I was able to follow most of what was discussed, even if I could not hold it all together long enough to see the grand picture. In this respect one can at least take consolation from the example of Einstein's humility when he writes:

"If I have learned one thing from all the pondering that has accompanied me through my long life, it is this: we are further removed from a deep insight into the elementary processes in our world than most of our contemporaries would believe" (p. 36).