J. Robert Oppenheimer

Early Life
Teaching and Research
Response to Nazis
Manhattan Project
Opposing the H-Bomb
McCarthy Hearings
Friend of Israel
Last Years

Early Life

J. Robert Oppenheimer (he said the J stood for nothing) was born into a wealthy Jewish family in New York City on April 22, 1904. His father, Julius, was a German immigrant who worked in his family’s textile importing business, and his mother, Ella Friedman, was a native New Yorker and painter. Their penthouse apartment had paintings by Van Gogh, Picasso, and other masters. The Oppenheimers were secular Jews, and Robert never had a bar mitzvah. Ray Monk, the author of Robert Oppenheimer: A Life Inside the Center, told the JTA, “To the outside world, he was always known as a German Jew, and he always insisted that he was neither German nor Jewish. But it affected his relationship with the world that that is how he was perceived.”

Oppenheimer was initially educated at Alcuin Preparatory School. In 1911, Oppenheimer entered the Ethical Culture Society School, a spin-off of Reform Judaism that believed in secular humanism. He graduated in 1921, but his further education was delayed a year by an attack of colitis contracted during a family vacation. He recovered in New Mexico, where he developed a love for horseback riding and the southwestern United States. 

Oppenheimer enrolled at Harvard in 1922 and majored in chemistry. After a course on thermodynamics, he became interested in experimental physics. He graduated summa cum laude in 1925 after only three years. A Harvard professor wrote in his recommendation for Oppenheimer to attend Cambridge, “Oppenheimer is a Jew, but entirely without the usual qualifications.”

He was accepted to Cambridge in 1924 but was bored, lonely, and felt he wasn’t “learning anything.” Oppenheimer despised his tutor, a popular physics professor Patrick Blackett, and confessed to leaving a poisoned apple on his desk. Blackett didn’t eat it, but Oppenheimer’s parents had to convince the university not to press criminal charges or expel him. He was placed on probation and was required to meet with a psychiatrist.

Reperiods of depression plagued Oppenheimer throughout his life, and he once told his brother, “I need physics more than friends.”

Oppenheimer realized his talent was for theoretical, not experimental, physics and left Cambridge in 1926 to study under Max Born at the University of Göttingen. He obtained his Doctor of Philosophy degree in 1927 at age 23.

Oppenheimer was awarded a United States National Research Council fellowship to the California Institute of Technology in 1927, which was split to allow him to spend time at Harvard.

Teaching and Research

After some time in Europe, Oppenheimer accepted an associate professorship from the University of California, Berkeley, but first had to recover from a bout of tuberculosis. He spent some weeks with his brother at a New Mexico ranch. Later, he used to say that “physics and desert country” were his “two great loves.”

His students and colleagues saw him as mesmerizing: hypnotic in private interaction but often frigid in more public settings. His associates fell into two camps: one saw him as an aloof and impressive genius and aesthete, the other as a pretentious and insecure poseur. His students almost always fell into the former category, adopting his walk, speech, mannerisms, and even his inclination to read entire texts in their original languages.

Oppenheimer did important research in theoretical astronomy (especially as related to general relativity and nuclear theory), nuclear physics, spectroscopy, and quantum field theory, including its extension into quantum electrodynamics. Although he doubted its validity, the formal mathematics of relativistic quantum mechanics also attracted his attention. His work predicted many later findings, which include the neutron, meson, and neutron star. In 1939, he and a colleague discovered black holes but didn’t recognize the importance and failed to pursue further research.

Response to Nazis

During the 1920s, Oppenheimer was not interested in politics. He claimed that he did not read newspapers or popular magazines. From 1934 on, he became increasingly concerned about international affairs. In 1934, he earmarked three percent of his annual salary for two years to support German physicists fleeing Nazi Germany. “I had a continuing, smoldering fury about the treatment of Jews in Germany,” he said later. “I had relatives there, and was later to help in extricating them and bringing them to this country. I saw what the Depression was doing to my students… And through them, l began to understand how deeply political and economic events could affect men’s lives.”

The same year, he tried to get one of his students (Robert Serber) a job but was blocked by Raymond Birge, the head of Berkeley’s physics department, who felt that “one Jew in the department was enough.”

Like many young intellectuals in the 1930s, Oppenheimer supported social reforms that were later alleged to be communist ideas. He donated to many progressive causes branded as left-wing during the McCarthy era. Most of his allegedly radical work involved hosting fundraisers for the Republican cause in the Spanish Civil War and other anti-fascist activities. He never joined the Communist Party, though he did pass money to leftist causes by way of acquaintances who were alleged to be party members.

After his father died in 1937, Oppenheimer inherited a small fortune.

Manhattan Project

When he joined the Manhattan Project in 1942, Oppenheimer wrote on his personal security questionnaire that he had been “a member of just about every Communist Front organization on the West Coast.” Years later, he claimed that he did not remember saying this, that it was not true, and that if he had said anything along those lines, it was “a half-jocular overstatement.” He was a subscriber to the People’s World, a Communist Party organ, and he testified in 1954, “I was associated with the communist movement.” From 1937 to 1942, Oppenheimer was a member at Berkeley of what he called a “discussion group,” later identified by fellow members as a secret unit of the Communist Party for Berkeley faculty.

The FBI opened a file on Oppenheimer in March 1941. The FBI noted that Oppenheimer was on the Executive Committee of the American Civil Liberties Union, which it considered a communist front organization. Shortly thereafter, the FBI added Oppenheimer to its Custodial Detention Index for arrest in case of a national emergency.

Brigadier General Leslie R. Groves, Jr., the director of the Manhattan Project, thought Oppenheimer too crucial to the project to be ousted over this suspicious behavior. On July 20, 1943, he wrote to the Manhattan Engineer District:

On October 9, 1941, two months before the United States entered World War II, President Franklin D. Roosevelt approved a crash program to develop an atomic bomb. In May 1942, National Defense Research Committee Chairman James B. Conant, one of Oppenheimer’s lecturers at Harvard, invited Oppenheimer to take over work on fast neutron calculations. One of his first acts was to host a summer school for bomb theory at his building in Berkeley. The mix of European physicists and his students—including Robert Serber, Emil Konopinski, Felix Bloch, Hans Bethe, and Edward Teller—kept themselves busy by calculating what needed to be done and, in what order, to make the bomb.

In September 1942, Leslie Groves was appointed director of what became known as the Manhattan Project. He selected Oppenheimer to head the project’s secret weapons laboratory. Groves was impressed by Oppenheimer’s singular grasp of the practical aspects of designing and constructing an atomic bomb and by the breadth of his knowledge. As a military engineer, Groves knew this would be vital in an interdisciplinary project involving not just physics but chemistry, metallurgy, ordnance, and engineering.

Oppenheimer and Groves decided they needed a centralized, secret research laboratory in a remote location for security and cohesion. Oppenheimer suggested a site near Santa Fe, New Mexico, where the Los Alamos Ranch School was located. The army took over some of the buildings and quickly erected new ones that became the Los Alamos Laboratory.

Oppenheimer recruited a group of the top physicists he called the “luminaries” by informing them of the German attempt to create an atomic bomb and the peacetime uses of nuclear energy. Six of the project’s eight leaders – Serber, Bloch, Bethe, Teller, Richard Feynman, and Victor Weisskopf – were Jewish. 

It soon turned out that Oppenheimer had underestimated the magnitude of the project. Los Alamos grew from a few hundred people in 1943 to more than 6,000 in 1945.

At this point in the war, there was considerable anxiety among the scientists that the Germans might be making faster progress on an atomic weapon than they were. When the Allies succeeded in removing the threat of a German atomic bomb through their military victories in 1944, Oppenheimer focused on making the atomic bomb to help bring a quick end to the fighting in the Pacific. He also felt that knowledge of the possible devastation caused by the bomb would force nations to work for peace.

The joint work of the scientists at Los Alamos resulted in the world’s first nuclear explosion near Alamogordo, New Mexico, on July 16, 1945. Oppenheimer had given the site the codename “Trinity” in mid-1944.

In 1965, Oppenheimer told an interviewer:

When the atomic bomb was used in Hiroshima (August 6) and Nagasaki (August 9), Oppenheimer was exhausted and deeply troubled, though he did not regret developing or using the bomb. He did say he wished it could have been ready to use against Germany.

Monk argues Oppenheimer’s personal problems were due to his denial of his Jewishness. His Jewish friend and colleague, Isidor Rabi said, “if he had studied the Talmud rather than Sanskrit…. It would have given him a better sense of himself.”

He resigned as director of the Los Alamos project. He traveled to Washington on August 17, 1945, to hand-deliver a letter to Secretary of War Henry Stimson expressing his revulsion and his wish to see nuclear weapons banned.

Opposing the H-Bomb

In October, Oppenheimer was granted an interview with President Harry Truman. The meeting went badly after Oppenheimer said he felt he had “blood on my hands.” The remark infuriated Truman and put an end to the meeting. Truman called him a “cry-baby scientist” and told his Undersecretary of State Dean Acheson, “I don’t want to see that son-of-a-bitch in this office ever again.”

Nevertheless, for his services as director of Los Alamos, Oppenheimer was awarded the Medal for Merit by President Truman in 1946.

The Manhattan Project did not become public knowledge until after the bombings of Hiroshima and Nagasaki. Oppenheimer’s prestige grew and he became the spokesperson for those who believed that the atomic age demanded a broader understanding of science and technology. He wrote articles and lectured on this subject, becoming a household name. His portrait appeared on the covers of Life and Time.

After the war, Oppenheimer accepted a professorship at Cal Tech and then, in 1946, went to the University of California at Berkeley. In 1947, he accepted an offer to direct the Institute for Advanced Study in Princeton, New Jersey, where Albert Einstein was a non-teaching faculty member.

Oppenheimer strongly influenced the Acheson- Lilienthal Report as a member of the Board of Consultants to a committee appointed by Truman. In this report, the committee advocated the creation of an international Atomic Development Authority, which would own all fissionable material and the means of its production, such as mines and laboratories and atomic power plants where it could be used for peaceful energy production. The plan was seen as an attempt to maintain the United States’ nuclear monopoly and was rejected by the Soviets. With this, it became clear to Oppenheimer that an arms race was unavoidable due to the mutual suspicion between the United States and the Soviet Union.

After the Atomic Energy Commission (AEC) came into being in 1947 as a civilian agency controlling nuclear research and weapons issues, Oppenheimer was appointed as the chairman of its General Advisory Committee (GAC). From this position, he advised on several nuclear-related matters, including project funding, laboratory construction, and even international policy – though the GAC’s advice was not always heeded. As chairman of the GAC, Oppenheimer lobbied vigorously for global arms control and funding for basic science and attempted to influence policy away from a heated arms race.

After the Soviets exploded their first A-bomb in August 1949, a schism developed between President Truman and his committee over developing a more destructive weapon.

Oppenheimer had been aware of the possibility of a thermonuclear weapon since the days of the Manhattan Project but had focused on the immediate need to develop a fission weapon. He subsequently opposed the development of such a “Super Bomb,” which he believed was unneeded and would cause enormous human casualties. Truman, however, was convinced by proponents of the hydrogen bomb and decided to proceed with its development.

Oppenheimer left the GAC when his term expired in August 1952 and was not reappointed.  

In 1948, Oppenheimer chaired the Department of Defense’s Long-Range Objectives Panel, which looked at the military utility of nuclear weapons, including how they might be delivered. Oppenheimer was also a member of the Science Advisory Committee of the Office of Defense Mobilization.

Oppenheimer participated in Project Charles in 1951, which examined the possibility of creating an effective air defense of the United States against atomic attack, and in the follow-on Project East River in 1952, which, with Oppenheimer’s input, recommended building a warning system that would provide one-hour notice to atomic attacks against American cities.

Oppenheimer also chaired the five-member State Department Panel of Consultants on Disarmament, which first urged that the United States postpone its planned first test of the hydrogen bomb and seek a thermonuclear test ban with the Soviet Union because avoiding a test might forestall the development of a catastrophic new weapon and open the way for new arms agreements between the two nations.

Oppenheimer became an influential figure because of his involvement in different government posts and projects and his access to crucial strategic plans and force levels. He also made political enemies because of his opposition to the development of the H-bomb and attracted greater scrutiny from the FBI, which had followed Oppenheimer since he showed communist sympathies as a professor at Berkeley.

McCarthy Hearings

On June 7, 1949, Oppenheimer testified before the House Un-American Activities Committee that he had associations with the Communist Party USA in the 1930s. In 1953, William Liscum Borden, who had been the executive director of the United States Congress Joint Committee on Atomic Energy, sent FBI Director J. Edgar Hoover a letter saying that “more probably than not J. Robert Oppenheimer is an agent of the Soviet Union.”

Shortly thereafter, Oppenheimer’s security clearance was suspended.  President Eisenhower asked him to resign, but he insisted on being given an opportunity to clear his name. At a secret hearing in April–May 1954, supporters and critics testified, and he denied being a member of the Communist Party.  He was not able to regain his clearance. 

Had Oppenheimer’s clearance not been stripped, he might have been remembered as someone who had “named names” to save his reputation. Instead, most of the scientific community viewed him as a martyr to McCarthyism.

“Oppenheimer took the outcome of the security hearing very quietly but he was a changed person; much of his previous spirit and liveliness had left him,” according to fellow physicist Hans Bethe.

In 2022, Secretary of Energy Jennifer Granholm vacated the 1954 revocation of Oppenheimer’s security clearance. She said, “In 1954, the Atomic Energy Commission revoked Dr. Oppenheimer’s security clearance through a flawed process that violated the Commission’s regulations. As time has passed, more evidence has come to light of the bias and unfairness of the process that Dr. Oppenheimer was subjected to while the evidence of his loyalty and love of country have only been further affirmed.”

Considered the father of the atomic bomb, Oppenheimer won several awards. In 1957, France made him an Officer of the Legion of Honor, and he was elected a Foreign Member of the Royal Society in Britain in 1962. President Lyndon Johnson presented Oppenheimer with the Enrico Fermi Award in 1963 (awarded by President Kennedy shortly before his assassination) “for contributions to theoretical physics as a teacher and originator of ideas, and for leadership of the Los Alamos Laboratory and the atomic energy program during critical years.”

Friend of Israel

Several biographies suggest he had little or nothing to do with Jewish causes and no interest in Zionism, but he was a strong supporter of Israel. Oppenheimer, along with Einstein, met with future Israeli President Chaim Weizmann in Princeton on November 11, 1947. Four years later, Oppenheimer and Teller met with Israeli Prime Minister David Ben-Gurion “to advise him regarding the best way to develop Israel’s plutonium reserves.”

Oppenheimer told Ben-Gurion he had discussed building a nuclear reactor with Weizmann and warned the prime minister about what he saw as a threat to Israel posed by Egypt’s relations with the Soviet Union. According to Saul Singer, “As a direct result of Oppenheimer’s pleading, Ben-Gurion became obsessed with the nuclear threat against Israel, and he quickly prepared a 10-year plan for the development of Israel’s nuclear program.” Toward that end, Weizmann went to the United States to discuss the idea. That year, 1958, construction of Israel’s nuclear reactor began in Dimona.

Contrary to other descriptions of Oppenheimer’s indifference to Judaism, Ben-Gurion said after meeting him in 1958 that he “had the impression that some sort of Jewish spark lit up the man.”

Oppenheimer later became an honorary fellow of the Weizmann Institute of Science and served as a member of its board of governors.

Last Years

Deprived of political power, Oppenheimer continued to lecture, write, and work on physics. His academic influence waned, however, as he published only five scientific papers after the war and none after 1950. Based on his earlier work, Oppenheimer was nominated for the Nobel Prize for physics three times but never won.

Along with Einstein, Bertrand Russell, and Joseph Rotblat, Oppenheimer established the World Academy of Art and Science in 1960 as a forum for scientists, artists, thinkers, and political and social leaders to address global challenges and the responsible and ethical advances of science.

Oppenheimer remained director of the Institute for Advanced Study in Princeton until he resigned in 1966 after being diagnosed with throat cancer (he was a chain smoker) in late 1965.

Oppenheimer married Katherine “Kitty” Puening in 1940, and they had two children. He died on February 15, 1967.

Oppenheimer is the subject of numerous biographies, including J. Robert Oppenheimer: The Brain Behind the Bomb (Inventors Who Changed the World) by Glenn Scherer and Marty Fletcher (2007) and Oppenheimer and the Manhattan Project: Insights into J. Robert Oppenheimer, “Father of the Atomic Bomb,” by Cynthia C. Kelly (2006). American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer (2005) by Kai Bird and Martin J. Sherwin, won the Pulitzer Prize for Biography or Autobiography in 2006 and served as the basis for the 2023 film Oppenheimer.

The 1980 BBC TV serial Oppenheimer won three BAFTA Television Awards. The Day After Trinity, a 1980 documentary about Oppenheimer and the building of the atomic bomb, was nominated for an Academy Award and received a Peabody Award. Oppenheimer’s life is also explored in Tom Morton-Smith’s 2015 play Oppenheimer, and in the 1989 film Fat Man and Little Boy. Also, in 1989, Oppenheimer was portrayed in the made-for-TV movie Day One. Composer John Adams wrote an opera entitled Doctor Atomic in 2005.

Sources: This is one of the 150 illustrated true stories of American heroism included in Jewish Heroes & Heroines of America: 150 True Stories of American Jewish Heroism, © 1996, written by Seymour Sy Brody of Delray Beach, Florida, illustrated by Art Seiden of Woodmere, New York, and published by Lifetime Books, Inc., Hollywood, FL. 
“J. Robert Oppenheimer: Life, Work, and Legacy,” Institute for Advanced Study.
“J. Robert Oppenheimer,” Atomic Heritage Foundation.
“J. Robert Oppenheimer,” Wikipedia.
“World Academy of Art and Science,” Wikipedia.
Sam Kean, “The Real Tragedy of Robert Oppenheimer,” Science History Institute.
Saul Jay Singer, “J. Robert Oppenheimer: Indifferent To Judaism, Concerned About Israel,” Jewish Press, (August 26, 2020)
Micaela Hester, “Jewish employees of the Manhattan Project,” Bradbury Science Museum, (April 1, 2021).
Or Rabinowitz and Yehonaton Abramson, “Imagining a Jewish Atom Bomb,” Tablet, (November 9, 2022)
Shira Li Bartov and Andrew Lapin, “The Jewish story behind ‘Oppenheimer,’ explained,” JTA, (July 19, 2023).

Photos: Portrait - Public domain via Wikimedia Commons.