The road to E=mc<sup>2</sub>

The title of this book, Einstein's Miraculous Year, is, of course, taken from the description that Dryden gave to the year 1666, the annus mirabilis in which the British fleet triumphed over the Dutch. It soon became the description of the two years, 1665 and 1666, when Isaac Newton created what was then modern physics.

To those of us in physics our annus mirabilis was 1905, which was the year that Albert Einstein created what we think of as modern physics. That was the year that Einstein published his first paper on relativity, which he followed with a very brief note in which he made the connection between mass and energy, E=mc2. This was also the year when he created what became in the next two decades the quantum theory; a theory that he ultimately rejected.

In addition, he wrote a paper on Brownian motion; the erratic motion of tiny particles suspended in, say, a liquid where they are bombarded by the invisible molecules of the liquid. This in itself was a paper that any other physicist might have been proud of but which looks a little pale besides the paper on relativity and the one on the quantum.

These papers have been available in English translations in various scattered sources, but now they have been collected in one small volume with a graceful foreword by Roger Penrose and very useful historical commentary by John Stachel, who is one of the founding editors of The Collected Papers of Albert Einstein. Much of this material can be found in the volume of this collection titled The Swiss Years: Writings, 1900-1909, which is also published by Princeton University Press. In addition to the great and rather familiar papers, Miraculous Year also includes Einstein's thesis, which is both unfamiliar and unreadable. As late as 1903, he had decided not to bother with a PhD but then changed his mind. In his own way, Einstein was very ambitious. He must have come to feel that having a PhD would advance his career, especially if he was to leave the Swiss National Patent Office, where he was a patent examiner, for a possible university post. In addition to being exceedingly dull, the thesis is full of mistakes, which Einstein and others corrected over the years. Only a true believer would plough through it now.

The obvious question is, for whom is the collection intended? The non-scientist would get about as much out of these papers as someone, not knowing Tibetan, who tried to read The Book of the Dead in the original. From a modern perspective it is not the mathematics that is difficult. There is no mathematics in these papers that would be beyond a suitably oriented university student.

What is difficult are the ideas. The relativity paper, whose mathematical parts use an antique notation that drives one slightly batty, is full of ideas; ideas that changed our notions of space and time. It contains the seemingly innocent statement that "If, for example, I say 'the train arrives here at 7 o'clock' that means, more or less, 'the pointing of the small hand of my watch to 7 and the arrival of the train are simultaneous events'." How Einstein got from this proposition eventually to E=mc2 is a miracle.

The one paper that Einstein himself considered at the time to be "revolutionary" is the quantum paper. I have read this paper many times and have even used it as the basis of some course lectures in modern physics. Each time I read it I am awed. How did the man - he was only 26 - steer this certain course among so many possibilities for confusion? The touch is absolutely sure. It is also full of predictions for do-able experiments. They were done over the next few decades, and it was for this work that Einstein was awarded the Nobel prize in 1921. The Swedish Academy was still, and it even said so, leery of the relativity theory.

Newton published most of his insights from the annus mirabilis in one great book, the Principia. People did not write papers in those days. I have often pondered the amusing idea of Einstein not publishing anything until he had created his general theory of relativity and gravitation in 1915 and then putting it all in one single book. In my fantasy, until that time no one would have heard of him or his work, and after the book was published it would have hit the world like a nuclear explosion.

Jeremy Bernstein is emeritus professor of physics, Stevens Institute of Technology, New Jersey, United States.