Compton, Arthur Holly (1892–1962), American physicist. Compton is generally regarded as one of the great figures in modern physics. A leader in the development of nuclear energy and investigations on cosmic rays, he discovered the effect that now bears his name in 1923. This discovery helped to establish that electromagnetic radiation has a dual nature, as a wave and as a particle. While at the University of Chicago, he was from 1942 to 1945 the director of the project that developed the first self-sustaining atomic chain reaction. He discovered the variation in the intensity of cosmic rays with the latitude and altitude of the observer and a method for the production of plutonium in quantity. In 1927 he was awarded, along with Charles T. R. Wilson, the Nobel Prize for Physics for his discovery of the Compton effect.