A bargain-bin book found its way into my Christmas stocking and has been a great holiday read. Einstein Wrote Back by John W. Moffat is the personal story of a self-taught physicist who corresponded with Albert Einstein about unified field theory.
The book is interesting because of Moffat’s unusual path to a career in physics and his willingness to reach out and engage the likes of Einstein. Moffat grew up during World War II in England, where the intense bombing routinely disrupted his education. Although he wasn’t admitted to a university, he was curious at age 19 and picked up books on cosmology and the evolution of stars.His reading motivated him to study physics and mathematics in his spare time. Using just library books, he completed the equivalent of an undergraduate education in physics in one year.
Moffat’s story shows where curiosity and determination can take you. In his case, his passion led him to read Einstein's papers and to write the great scientist, asking about his attempts at a unified field theory.
During his later years, Einstein attempted to unify, in one mathematical framework, the forces of gravity and electromagnetism.
Gravity decreases when the distance between two masses increases, according to a well-known mathematical law. Similarly, the force between two charged objects decreases as they move apart, following the same mathematical law.
In fact, both forces are described with precise equations. The simple form of gravity is given by Newton’s Law, but a more-sophisticated mathematical description (which supersedes Newton’s Law) is given by Einstein’s equations of general relativity.Similarly, the forces of electricity and magnetism are given by Maxwell’s equations, formulated by Scottish physicist James Clerk Maxwell in the 1860s.
Because both gravity and electromagnetism are described by mathematical equations, it seems as if it should not be that difficult to merge both into a single, unified theory.
But it is difficult. In fact, it is one of the greatest challenges in physics. Even Einstein came up short.
Moffat, however, had an idea of how to tweak Einstein’s method and wrote him about it. Einstein wrote back, commenting in general about his ideas of unification.
Today, Moffat is retired from the University of Toronto, where he published several theoretical papers about modifications to Einstein’s theory of general relativity.
Many scientists continue to look for a better mathematical description of nature. Newton improved upon Aristotle, and Einstein improved upon Newton. It often takes many years before the technology becomes possible to test fundamental theoretical ideas. Although Einstein’s theory was published in 1917, there was only tentative evidence that it was correct even into the 1950s.Only in the past 10 years has there been convincing evidence that one mathematical term in Einstein’s equations, called the cosmological constant, actually exists.
Today, with astronomical observations of “dark matter” and “dark energy,” it now is clear that some deeper scientific theory is necessary to describe our universe. And as we turn the calendar to 2013, the search for a complete mathematical description of nature goes on.
Kenneth Hicks is a professor of physics and astronomy at Ohio University in Athens.