After Einstein graduated from ETH he could not find a university teaching position, so he took a job in 1902 at the patent office in Bern, where he evaluated patent applications for electromagnetic devices. During this time he formed a discussion group in which he met with friends to discuss science and philosophy. Einstein's job in the patent office may have influenced his later thinking, since many of the patents he handled had to do with the synchronization of electrical and mechanical signals. This experience helped him establish many of the questions about the fundamental nature of light and connections between space and time.
While he was working in the patent office he published four papers in Annalen der Physik, the top German physics journal at the time. These papers have become known as the annus mirabilis (extraordinary year) papers because of their far-reaching implications and importance. His first paper in this group was on the particulate nature of light and how the photoelectric effect could be understood as light behaving as discrete quanta of energy. His next annus mirabilis paper was on Brownian motion, explaining the random movement of small objects as being caused by molecular action, supporting the atomic theory. Einstein's third paper in this series was on special relativity, where he showed that the speed of light was independent of the observer's speed or state of motion. His final annus mirabilis paper was perhaps his most famous; in it he derived the equivalence of mass and energy as described by the equation
showing that mass could be converted into energy and predicting the future development of nuclear power. Although modern science recognizes these papers as remarkable achievements and some of the most important works in physics of all time, the physics community barely noticed them, and many actually rejected them as nonsense. At the age of 26 Einstein earned a Ph.D. from ETH under the direction of Alfred Kleiner, after submitting his dissertation, "A New Determination of Molecular Dimensions."
Albert Einstein, shown writing an equation for the density of the Milky Way Galaxy at Carnegie Institution, Mount Wilson Observatory headquarters, Pasadena, California, on January 14, 1931 (AP Images)
Continue reading here: Later scientific contributions
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