Book Reviews - Winter 2005

What Einstein Knew


One year and five papers that changed physics forever

By Tony Rothman

December 1, 2004


Einstein 1905: The Standard of Greatness, By John S. Rigden, Harvard University Press, $21.95

The Einstein Almanac, By Alice Calaprice, Johns Hopkins University Press, $24.95

Two thousand five promises to be a good year for centennials. Historians will mark the hundredth anniversary of the first Russian revolution; music lovers may celebrate a century of Juilliard and Richard Strauss’s Salome, literati the hundredth birthday of Jean-Paul Sartre. Danish astronomers will remember that one hundred years ago Ejnar Hertzsprung took the first steps toward understanding stellar evolution, while students of popular culture might light a candle to Greta Garbo and the first regular nickelodeon. Physicists, though, know that none of this matters. Only one thing of lasting significance took place in 1905: twenty-six-year-old Albert Einstein wrote five papers that changed the face and foundation of physics forever.

Einstein’s feat has never been equaled in the history of science. During merely six months of that annus mirabilis, Einstein created his special theory of relativity, proposed E=mc2, made the best calculation of the size of molecules, helped finalize the very concept of molecules by explaining the random motion of pollen suspended in water, and explained the mysterious “photoelectric effect” by proposing that light travels in energy packets known as quanta. At least three of these papers are among the greatest ever written in physics; for the last he received the 1921 Nobel Prize.

The celebrations marking this unparalleled achievement have long been under way. Princeton University Press, which has been publishing The Collected Papers of Albert Einstein since 1987, opened the floodgates as early as 1998 with its reissue of the five papers as Einstein’s Miraculous Year. Both Discover and Scientific American magazines released special Einstein issues in September 2004. In honor of Einstein, the UN has designated 2005 the World Year of Physics; conferences and symposia are springing up everywhere and the centennial books and screen savers are now arriving.

Strangely, the festivities embody a paradox, perhaps a double paradox: On the one hand, more has been written about Einstein than any scientist who ever lived, and to say anything fresh is almost impossible. The superfluity can only cause problems for publishers and conference organizers wishing to be original. On the other hand, Princeton’s publication of the Collected Papers as well as diligent sleuthing by historians have allowed a more nuanced view of Einstein to emerge. Any subtleties are so utterly defeated by the public mythology surrounding the man, however, that the traditional incantations continue to be repeated by journalists and scientists alike.

Reading “The Master’s Mistakes” in Discover, for instance, you’ll learn that Einstein’s errors were so profound that ordinary scientists would be glad to have made them. True enough in at least one case, but the fact is that Einstein often made mistakes that were just mistakes. In his special relativity paper he clearly misinterpreted the deflection of starlight known as “aberration”—one of the principal phenomena he devised the theory to explain. It is also universally claimed that with this famous paper Einstein married space and time into a “spacetime continuum.” Implicitly true, but he never refers to time as the fourth dimension in his early work; the formal union was carried out by Hermann Minkowski in 1908—and Einstein initially opposed the idea! Another pedestal of Einstein lore is that he developed relativity while remaining unaware of the scientific developments of his time. Yes, he gives no references, but one need only read his letters to his fiancée Mileva Maric in the Collected Papers to know that he had a pretty good idea of what was going on around him.

The centennial crop of books also seems designed less to challenge than to celebrate. One of them, The Einstein Almanac, is from Alice Calaprice, who has made a cottage industry of the lighter side of Einstein, previously compiling The Quotable Einstein and Dear Prof. Einstein. The Almanac is exactly what its title says: a well-illustrated chronology of the major events in Einstein’s life. Don’t look for in-depth analyses here, but you will find a surprisingly complete summary of his publications, all framed by interesting sidelights on the other scientific and world events of the times.

For the more scientifically inclined, John Rigden’s Einstein 1905: The Standard of Greatness offers a synopsis of the five papers on a level that high school seniors or college freshmen might appreciate. For each paper Rigden presents sound scientific explanations, as well as a discussion of the historical context and the reaction of the scientific community.

Rigden’s history follows established tradition. One chapter is entitled “The Merging of Space and Time,” although, as mentioned, the paper did not regard time as a fourth dimension. In the E=mc2 chapter, Rigden claims that no one anticipated the famous equation, that it came out of the blue. But this is not entirely the case. The relationship between energy and mass had been proposed in several isolated instances, and several weeks before Einstein did, the great mathematician Henri Poincaré— Einstein’s rival in the race to relativity and to whose book Science and Hypothesis Einstein was indebted for several seminal ideas—actually wrote down an expression from which E=mc2 follows immediately. Why Poincaré didn’t explicitly write down the equation remains a puzzle. It is also an oversimplification to say that Einstein proved E=mc2. He proposed it for a particular sort of system and showed that in this case it was approximately true. Only in 1911, apparently, did Hendrik Lorentz prove that E=mc2 was a universal truth.

The centennial festivities proceed, but those tempted less by celebration than by historical nuance might go back to Einstein’s Miraculous Year. Although the papers themselves are technical, the commentary provided by editor John Stachel is insightful without rising much above the level of Rigden’s book. Those willing to decide for themselves what Einstein knew and what he didn’t should go to the nearest university library and try the ur-text itself: The Collected Papers. The early letters aren’t technical and have the advantage of being from the horse’s mouth. A satisfying alternative is historian Jagdish Mehra’s very readable Golden Age of Theoretical Physics, which not only contains a thoughtful chapter on special relativity but essays on most of the other major developments of twentieth-century physics.

Many more Einstein offerings are on the horizon. Judging from what has appeared, don’t expect profundities. Instead, accept these contributions for what they are: a tribute to a great genius.

Tony Rothman is a cosmologist and writer. His latest book is Everything's Relative and Other Fables from Science and Technology.

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