Planck, Max (Karl Ernst Ludwig)

(born April 23, 1858, Kiel, Schleswig—died Oct. 4, 1947, Göttingen, W.Ger.) German physicist. He studied at the Universities of Munich and Kiel, then became professor of theoretical physics at the University of Berlin (1889–1928). His work on the second law of thermodynamics and blackbody radiation led him to formulate the revolutionary quantum theory of radiation, for which he received a Nobel Prize in 1918. He also discovered the quantum of action, now known as Planck's constant, h. He championed Albert Einstein's special theory of relativity, but he opposed the indeterministic, statistical worldview introduced by Niels Bohr, Max Born, and Werner Heisenberg after the advent of quantum mechanics. As the influential president of the Kaiser Wilhelm Society (later the Max Planck Society) until his resignation in 1937, he appealed to Adolf Hitler to reverse his devastating racial policies. His son was later implicated in the July Plot against Hitler and was executed.