Julius Robert Oppenheimer (April 22, 1904 - February 18, 1967) was a Jewish-American physicist and the director of the Manhattan Project, the World War II effort to develop nuclear weapons, at the Los Alamos National Laboratory in New Mexico.

Oppenheimer was born in New York in 1904. He studied at the Ethical Culture Society school where, in addition to mathematics and science, he was exposed to a variety of subjects ranging from Greek to French literature. He entered Harvard one year late due to an attack of colitis, and he made up for the delay by graduating in just three years with a major in chemistry. One of the most brilliant men of the twentieth century, he could study science and the humanities with equal ease and insight.

After his graduation, Oppenheimer became interested in theoretical physics and studied under Max Born at the University of Göttingen for his PhD. He had a true feel for languages and could study a new one in a period of just one or two months. During the period spent at Göttingen, Oppenheimer published many important contributions to the then-newly developed quantum theory. After studying at Göttingen, Oppenheimer returned to the United States, where he took a teaching post at the University of California, Berkeley and eventually became a professor of physics. There he inspired a whole generation of physicists who idolized him for his intellectual virtuosity and amazingly versatile interests.

Oppenheimer (right) with Albert Einstein

Oppenheimer did important research in astrophysics, nuclear physics, and spectroscopy. When World War II started, Oppenheimer was persuaded to join the war effort to develop an atomic bomb, and he threw himself into the task with full vigor. He became director of the Los Alamos Laboratory in New Mexico where the bomb was being developed. At Los Alamos, he collected a group of the most brilliant physicists of his day, which included Enrico Fermi, Hans Bethe, Richard Feynman, Edward Teller, and Victor Weiskopf. He succeeded superbly as director and kept all the details, from chemistry to engineering, of the project in his mind. The joint work of the scientists at Los Alamos resulted in the first nuclear explosion at Alamogordo on July 16, 1945. Witnessing the explosion is said to have recalled a verse in Sanskrit from the Bhagavad Gita: Kalosmi lokaksaya krt pravrddho - "I am Death, destroyer of worlds."

After the Nazis surrendered and the bomb was dropped on Hiroshima and Nagasaki in Japan, Oppenheimer objected to these weapons being used to defend the United States from the Soviet Union. He became Chairman of the General Advisory Committee of the Atomic Energy Commission, and rallied vigorously for arms control.

His close ties to Communists and his leftist politics led to tensions between him and politicians, and he was accused of being a security risk. This led to a much publicized hearing, and despite support from dozens of fellow scientists and colleagues, his security clearance was withdrawn. Edward Teller, with whom Oppenheimer disagreed on whether the more powerful hydrogen bomb should be developed, did not support Oppenhemier in his hearing. Later on he was reinstated by President Lyndon Johnson and was awarded the Enrico Fermi Award as a sign of gratitude for his services to the nation.

In his last years, Oppenheimer was the director of the Institute for Advanced Study at Princeton. He died in 1967.