BOSTON — EINSTEIN'S MIRACULOUS YEAR: FIVE PAPERS THAT CHANGED THE FACE OF PHYSICS
Edited by John Stachel
Princeton University Press
198 pp., $19.95
You know it at first glance. The unkempt hair, the gray mustache, the thoughtful gaze. Albert Einstein's mature face is an icon of 20th-century science.
But 93 years ago, he wore the unknown face of an emerging physicist eager for recognition. He secured it with a burst of publications in 1905 that brought classical physics to its climax and laid the foundation for a revolution in our perception of the physical world.
Such was the "miraculous year" of this century's greatest physicist. Scholars can study it in exquisite detail in "The Collected Papers of Albert Einstein," edited by John Stachel of Boston University. Now Professor Stachel has made its essence available for the rest of us in a slim book that features those five landmark papers in fresh English translations.
The technical stuff is heavy going. But the extensive commentary repays perusal. It puts Einstein's work into historical perspective. Many physicists didn't believe in atoms and molecules in 1905. Einstein hit that skepticism head on. His doctoral thesis showed how to estimate the size of molecules. A second paper derived laws that govern the dance of small particles suspended in liquid. These papers and the research of others they inspired did much to bring the skeptics around.
Two more papers sketched out Einstein's famous theory of special relativity. The commentary clears away two popular myths. First, Einstein didn't invent the concept of relativity. That harks back to Galileo and Newton. Simply put, it specifies that physical laws should have the same form for all observers moving relative to each other at constant speeds.
Second, Einstein didn't upset Isaac Newton's apple cart. That happened in the mid-19th century when physicists found that Newton's dynamics of particles and forces didn't jibe with Clerk Maxwell's laws of electromagnetism.
Einstein realized that the trouble lay in naive assumptions about the absolute nature of space and time. He replaced Newton's concept of absolute time, the same for all observers, with the concept of the absolute speed of light. Different observers moving relative to each other would clock different times for events. But they would all measure the same light speed.
With that fix, classical mechanics and electromagnetism melded harmoniously into a system that satisfied the demands of relativity. Its most important upshot was the startling conclusion that mass and energy are equivalent.
But while he saved the classical physicists' bacon, Einstein jawboned them about the flaws in their world view. He said radically new concepts were needed to explain what they were learning about the structure of matter and radiation. In his fifth 1905 paper, he advanced the idea that light acts as both waves and as particles. He showed this could explain such puzzling phenomena as how photo cells work. It won him a 1921 Nobel Prize.
It's ironic that Einstein never accepted the quantum theory in which other physicists extended wave-particle dualism throughout the submicroscopic realm. Quantum theory explains much about the structure of matter to an accuracy never before achieved, but Einstein considered it in need of radically new insights, and so do modern physicists.
As British theorist Roger Penrose notes in his introduction to this book, what those insights are "only time and, I believe, a new revolution will tell - in perhaps some other Miraculous Year."
* Robert C. Cowen writes on science for the Monitor.