George Eugene Uhlenbeck
George Eugène Uhlenbeck (December 6, 1900 – October 31, 1988) was a Dutch-American physicist who, with Samuel Abraham Goudsmit, proposed the concept of electron spin. Uhlenbeck was born in Jakarta, Indonesia when Indonesia was a Dutch colony and Jakarta was named Batavia. His father was officer in the Dutch-East-Indian army. In the thirties Uhlenbeck emigrated to the United States; he died in Boulder Colorado where his son was professor in biochemistry.
In 1925, as physics graduate student at the University of Leiden, he and Goudsmit put forth their idea of electron spin to explain certain regularities that were observed in the spectra of atomic hydrogen and helium. Initially they thought that electrons rotate physically about an axis, hence the term spin; later that point of view turned out to be unattainable, the rotational speeds required to explain the empirical phenomena would simply be too high. 
Uhlenbeck joined the physics department at the University of Michigan, Ann Arbor, USA, in 1927, returned to The Netherlands, as professor at the University of Utrecht, and then went back to the USA for good, becoming full professor at the University of Michigan in 1939. From 1943 to 1945 he worked at the Radiation Laboratory of the Massachusetts Institute of Technology. In 1961 Uhlenbeck left Michigan, where he had been the Henry Cahart Professor of Physics since 1954; he was appointed professor and physicist at the Rockefeller Medical Research Center at the State University of New York, New York City, becoming professor emeritus in 1971. He wrote many papers on atomic structure, quantum mechanics, Brownian motion, and nuclear physics.
Uhlenbeck and Goudsmit were awarded the Max Planck medal in 1964. Uhlenbeck was also awarded the Lorentz medal in 1970 and Wolf Prize in Physics in 1979. In addition, Uhlenbeck served as President of the American Physical Society in 1959.
- Their letter: Ersetzung der Hypothese vom unmechanischen Zwang durch eine Forderung bezüglich des inneren Verhaltens jedes einzelnen Elektrons [Replacement of the hypothesis of non-mechanical force by a requirement regarding the internal behavior of every single electron] appeared in Die Naturwissenschaften, vol. 13, pp. 953-54 (1925).