J. Robert Oppenheimer

J. Robert Oppenheimer was born in New York City on April 22, 1904, to Julius Oppenheimer, a wealthy textile importer, and Ella Friedman Oppenheimer, a painter; he had a younger brother, Frank Oppenheimer. The family belonged to the Ethical Culture Society, and he entered the Ethical Culture School in September 1911, graduating as valedictorian of his high school class in 1921.⁠[1][2]

After graduating he contracted dysentery in Germany and was too ill to start college, and in spring 1922 he went to New MexicoNew MexicoNew Mexico is a state in the Southwestern United States. Its capital is Santa Fe and its largest city is Albuquerque. It was admitted to the Union on January 6, 1912, as the 47th state, and had a population of 2,117,522 in the 2020 census (April 1, 2020).Open the full entry. In fall 1922 he entered Harvard UniversityHarvard UniversityHarvard University is a private research university in Massachusetts, established by the Massachusetts Bay Colony legislature in 1636 and named in 1639 for early benefactor John Harvard. Its principal campuses are in Cambridge and the Allston and Longwood neighborhoods of Boston. It includes Harvard College, graduate and professional schools, and the Radcliffe Institute for Advanced Study. Two governing boards share oversight. Alan M. Garber was president as of October 2026, and the endowment stood at $56.9 billion at the end of fiscal 2025.Open the full entry, majoring in chemistry before turning to physics, and completed the normal four-year course in three years, graduating summa cum laude in 1925.⁠[1][3][2]

In 1925–1926 he did graduate work at the Cavendish Laboratory in Cambridge, England, under J. J. Thomson, and in 1926 moved to the University of Göttingen, where he received his Ph.D. in physics under Max Born in spring 1927. That year he and Born published “Zur Quantentheorie der Molekeln,” which separated the motion of electrons from that of nuclei in molecules. He then held a National Research Council fellowship at Harvard and at the California Institute of Technology, and in 1928–1929 an International Education Board fellowship at Leiden and Zürich.⁠[3][2]

In 1929 Oppenheimer became an assistant professor at both the University of California, BerkeleyUniversity of California, BerkeleyThe University of California, Berkeley (UC Berkeley) is a campus of the University of California system; the University of California was founded in 1868 through a merger of two institutions and moved to Berkeley, California, in 1873.Open the full entry, and the California Institute of Technology, and in 1936 a full professor at both. In 1939 he published “On massive neutron cores” with G. M. Volkoff and “On continued gravitational contraction” with H. Snyder; the National Park Service account describes this as important original work on neutron stars and black holes.⁠[3][1]

In 1936 he began a relationship with Jean Tatlock, a medical student and Communist Party member who introduced him to left-wing politics; it ended in early 1939. Unlike his brother Frank Oppenheimer, he never joined the Communist Party.⁠[1]

In early 1941 Oppenheimer began working with Ernest Lawrence on atomic bomb questions. In spring 1941 the Franklin D. RooseveltFranklin D. RooseveltFranklin D. Roosevelt (1882–1945) was an American politician who served as the 32nd president of the United States from 1933 to 1945, the only president elected four times; he led the country through the Great Depression and World War II and greatly expanded the federal government’s role through the New Deal.Open the full entry administration, after receiving a British report, created the S-1 Committee, which named Oppenheimer its coordinator for fast-neutron research; in October 1941 Lawrence brought him into a secret meeting on the atomic bomb.⁠[4]

On September 18, 1942, General Leslie GrovesLeslie GrovesLeslie Groves (1896–1970) was a United States Army general who headed the Manhattan Project, the World War II effort to develop the atomic bomb.Open the full entry took charge of S-1’s work and the Manhattan Engineer District was established. On October 15 Groves asked Oppenheimer to head the weapons laboratory known as Project Y; at Oppenheimer’s suggestion the two selected the Los Alamos mesa in New Mexico, site of the Los Alamos Ranch School, as Site Y on November 16, and the army began buying land two days later.⁠[4][2]

The Los Alamos laboratory was established in 1943 to conduct scientific research for the Manhattan Project, and Oppenheimer, hired by Groves, became its first director, leading the development of the atomic bomb from 1943 to 1945; Los Alamos National Laboratory says he led the team for 27 months.⁠[5][6][7]

Military intelligence kept him under surveillance during the war and observed his June 1943 visit to Jean Tatlock in San Francisco.⁠[4]

On July 16, 1945, Oppenheimer witnessed the successful Trinity test in central New Mexico. Afterward he said “it worked” to his brother Frank Oppenheimer; in 1965 he recalled that a line from the Bhagavad Gita about becoming Death, the destroyer of worlds, had come to his mind.⁠[2][4]

In October 1945 Oppenheimer met President Harry S. TrumanHarry S. TrumanHarry S. Truman (1884–1972) was an American politician who served as a U.S. senator from Missouri and as vice president in 1945, succeeding Franklin D. Roosevelt on his death that year and serving as the 33rd president of the United States from 1945 to 1953, a period spanning the end of World War II and the early Cold War.Open the full entry; on October 16 he resigned as director of the Los Alamos laboratory to take a post at the California Institute of Technology, and in November the family moved to Pasadena. In 1946 Truman presented him with the Medal for Merit.⁠[4][2][3]

In 1947 the Atomic Energy Commission (AEC) took over from the military, beginning civilian control of nuclear energy in the United StatesUnited StatesThe United States is a federal country in North America made up of 50 states, the District of Columbia as the seat of government, and territories such as Puerto Rico and Guam; its capital is Washington, D.C. The Continental Congress adopted the Declaration of Independence on July 4, 1776. The 2020 census (April 1, 2020) counted a resident population of 331,449,281, and the 435 seats of the House of Representatives are apportioned among the states on the basis of the census.Open the full entry. Oppenheimer chaired the AEC’s General Advisory Committee until 1952 (the biographical memoir by H. A. Bethe for the National Academy of Sciences dates the start of his chairmanship to 1946).⁠[8][3]

In 1949 the Soviet Union detonated its first atomic bomb and Truman announced the U.S. hydrogen bomb program. Oppenheimer opposed developing the hydrogen bomb, which made him political enemies. In 1952 a successful U.S. hydrogen bomb test produced a blast 500 times larger than Little Boy.⁠[8][2]

From 1947 to 1966 Oppenheimer was director of the Institute for Advanced Study in Princeton, New JerseyNew JerseyNew Jersey is a state in the eastern United States on the Atlantic Ocean, bordered by New York State, Delaware, and Pennsylvania, with the Hudson River forming its northeastern boundary and the Delaware River its western boundary; its capital is Trenton and its largest city is Newark. One of the original 13 colonies, it became the third state to ratify the U.S. Constitution on December 18, 1787, and its population in the 2020 census (April 1, 2020) was 9,288,994.Open the full entry, succeeding Frank Aydelotte (1939–1947); he was followed by Carl Kaysen (1966–1976).⁠[9][7]

In December 1953 the AEC suspended Oppenheimer’s security clearance pending an investigation and gave him the choice of giving up the clearance and resigning from the AEC or appearing before an investigatory board; he chose the hearing.⁠[10]

The Personnel Security Board, chaired by Gordon Gray, held hearings in Washington, D.C., from April 12 to May 6, 1954. His defense lawyer was never granted clearance to review classified documents. On May 27 the board voted 2–1 to recommend that his clearance not be reinstated; it found “no evidence of disloyalty” but based its recommendation on his past associations and his opposition to the hydrogen bomb. The AEC’s general manager, K. D. Nichols, recommended affirmance on different grounds, focusing on his candor about his associations and the associations themselves.⁠[11][10]

On June 29, 1954, the AEC voted 4–1 to affirm the board’s recommendation, revoking his clearance two days before his consulting contract was to expire; the Atomic Heritage Foundation puts it at 32 hours before the clearance was set to expire. The AEC published a redacted transcript later that year.⁠[11][2][10]

The AEC selected Oppenheimer for its 1963 Enrico FermiEnrico FermiEnrico Fermi (1901–1954) was an Italian-American physicist who received the 1938 Nobel Prize in Physics and in 1942 led the team that achieved the first controlled nuclear chain reaction in Chicago.Open the full entry Award in recognition of his leadership in atomic development and its peaceful applications. The award was decided by President John F. KennedyJohn F. KennedyJohn F. Kennedy (1917–1963) was an American politician who represented Massachusetts in the U.S. House of Representatives and the U.S. Senate and served as the 35th president of the United States from 1961 to 1963. The youngest person elected president and the first Roman Catholic to hold the office, he was assassinated in Dallas on November 22, 1963.Open the full entry and presented by President Lyndon B. JohnsonLyndon B. JohnsonLyndon B. Johnson (1908–1973) was an American politician who served Texas as a U.S. representative and senator and led the Senate Democrats, became vice president in 1961 and succeeded to the presidency on the assassination of John F. Kennedy in 1963, serving as the 36th president of the United States from 1963 to 1969. His administration enacted the Civil Rights Act of 1964 and other “Great Society” legislation while expanding the U.S. military commitment in the Vietnam War.Open the full entry on December 2, 1963; the National Park Service account dates the presentation to 1964 and names Edward Teller as his nominator.⁠[12][3][2][8]

Oppenheimer was diagnosed with throat cancer in 1966, the year he stepped down as director of the Institute for Advanced Study. He died of throat cancer in Princeton, New Jersey, on February 18, 1967, at the age of 62, and his ashes were scattered at sea off St. John in the U.S. Virgin Islands.⁠[8][2][6]

In April 2022 Los Alamos National Laboratory Director Thom Mason and eight former directors urged the Department of Energy to act. On December 16, 2022, Secretary of Energy Jennifer M. Granholm signed a secretarial order vacating the AEC’s decision of June 29, 1954; as the AEC’s successor agency, the department said it was responsible for correcting the historical record.⁠[10][11][12]

The order found that the AEC had violated its own procedures: prosecuting attorneys Roger Robb and Arthur Rolander assisted the Personnel Security Board for a week before the hearing and took part in its deliberations without Oppenheimer or his counsel present, and Oppenheimer’s side was given no chance to rebut the general manager’s letter. The order states that “the AEC failed to follow its own rules” while adding that “we will not reconsider the substantive merits.” In her statement Granholm said that over time “the evidence of his loyalty and love of country have only been further affirmed.”⁠[11][12]

Oppenheimer met Katherine “Kitty” Puening in 1939, and they married on November 1, 1940. His wife, Kitty Oppenheimer, was a botanist. They had two children, Peter and Toni; Peter was born in May 1941.⁠[1][2]

The Department of Energy honored him by creating the Oppenheimer Science and Energy Leadership Program in 2017. Encyclopaedia BritannicaEncyclopædia BritannicaEncyclopædia Britannica is a general English-language encyclopedia first published in Edinburgh, Scotland, in 1768; the name also refers to its publisher, Chicago-based Encyclopædia Britannica, Inc. (which presents itself as The Britannica Group). The print edition ended in 2012, and the company’s main businesses since then have been the online encyclopedia Britannica.com, digital education products for schools and libraries, and Merriam-Webster dictionaries.Open the full entry judges that his security case became a cause célèbre in the scientific world. Los Alamos National Laboratory describes its first director and Los Alamos as intrinsically connected.⁠[12][7][6]

Los Alamos National Laboratory: Official website: https://www.lanl.gov/ (opens in a new window).⁠[5]

Institute for Advanced Study: Official website: https://www.ias.edu/ (opens in a new window).⁠[9]