Albert Abraham Michelson (1852-1931)

American physicist, born in Strelno, Prussia, on 19 December 1852. His family emigrated to America when he was a young child. He studied at the US Naval Academy and several institutions in France and Germany, and became Professor of Physics at Cleveland, Ohio, in 1883.

He developed the Michelson interferometer to study variations in the speed of light caused by the aether (a medium thought to permeate space). During the 1880s Michelson and Edward Morley carried out a series of experiments, but could find no variation in the speed of light. Albert Einstein’s 1905 special theory of relativity postulated that the speed of light is constant and removed the need for an aether. In 1907 Michelson became the first American scientist to be awarded the Nobel Prize for Physics.

In the 1920s Michelson used his interferometry techniques to measure the diameter of the star Betelgeuse, obtaining the first accurate measurement of a star’s size. He died on 9 May 1931, in Pasadena, California.