George E. Uhlenbeck, 87, a major figure in theoretical physics and a professor emeritus at Rockefeller University. The physicist was best known as the co-discoverer, with the late Samuel A. Goudsmit, of the phenomenon of electron spin. This discovery that electrons spin proved to be a cornerstone of basic atomic theory. Uhlenbeck was born in Batavia, Java, which is now Jakarta, the capital of Indonesia. He received his doctorate in 1927 from the State University of Leiden in the Netherlands. He and Goudsmit made their landmark discovery about electron spin as graduate students there. He joined Rockefeller University, formerly the Rockefeller Institute for Medical Research, in 1961 to help establish its theoretical physics faculty. Uhlenbeck became a member of the National Academy of Sciences in 1955. He received the National Medal of Science, the nation’s highest science award, in 1977, the same year the Dutch government made him Commander of the Order of Orange-Nassau, the highest non-military award it gives to foreigners. In Boulder, Colo., on Monday.