NON- FICTION

The Formative Years of Relativity by HANOCH GUTFREUND & JÜRGEN RENN

Princeton 2017) RRP $ 75.00 Hardcover

IN 1921 ALBERT EINSTEIN visited the United States and caused a sensation. It was two years since Arthur Eddington had led an expedition to witness a solar eclipse off the coast of Equatorial Guinea and confirmed Einstein’s prediction that the Sun’s gravity would bend distant starlight – the event that launched Einstein to celebrity. One year later Einstein would be awarded the Nobel Prize.

In May that year Einstein gave five lectures at Princeton that summarised his thoughts on his new theory of general relativity. The text of those lectures, published as The Meaning of Relativity, has been in print ever since. This new volume includes the text, two previously unpublished popular lectures by Einstein, and extensive context.

The two co-authors, Gutfreund (a theoretical physicist) and Renn (a science historian) tell the story of those formative years. While the popular portrayal has Einstein gifting the fully formed theory of gravitation to the world in 1915, the reality was rather different. Einstein was aided by many of his contemporaries, and continued to struggle with the theory long after 1915. His underlying ideas changed radically over the next decade.

These transformations are captured in his correspondences with the scientists, philosophers and mathematicians of his time. Gutfreund and Renn do a wonderful job in following Einstein’s lines of thought, and in highlighting the input of more than two dozen others who contributed to the theory.

Along the way, the authors treat us to some singular Einstein anecdotes. In 1916, one of Einstein’s friends, the physicist and politician Friedrich Adler, assassinated the prime minister of Austria in protest over the war. Einstein drafted a letter to Emperor Charles I to ask for Adler’s pardon. On the back of the letter, Einstein scribbled down equations attempting to describe the size and shape of the universe.

The book also describes the debate over whether or not gravitational waves exist, and how Einstein flip-flopped on the issue at least four times. The debate over the meaning of the singularity that appeared at the ‘Schwarzchild radius’ is especially interesting. Nobody at the time could conceive that the singularity might exist in reality – what we now know as a black hole.

While certainly readable, Gutfreund and Renn’s style is a tad dry, and critical ideas in physics are sometimes left unexplained. The book will suit readers who are already familiar with the basic ideas of general relativity, and who want to learn about how the theory was formed. As a science history, this book is a testament to Einstein’s genius and humility, and also to the process of science itself – with all the pitfalls, blunders and dead ends that precede any meaningful forward step. And this step was nothing less than a revolution.