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J. Robert Oppenheimer: Father of the Atomic Bomb


My writing interests are general, with expertise in science, history, biographies, and “how-to” topics. I have written over sixty books.


Early Life

Julius Robert Oppenheimer was born in New York City on April 22, 1904. His father was a wealthy textile importer and his mother was a painter. Robert was a quick learner with a wide-ranging curiosity. He attended the Ethical Culture School in New York, graduating in 1921. After graduation he went for a summer trip to Germany to visit relatives. On a field trip to collect mineral samples in Bohemia, he contracted dysentery and became very ill. He spent the next winter recovering at his parents’ home in New York. During the summer of 1922 his father sent him with his English teacher, Herbert W. Smith, to explore the trails and plateaus of New Mexico. This trip would instill in him a lifelong love of the desert southwest.

In the fall of 1922, Oppenheimer entered Harvard University to study chemistry. A gifted student, he took more than a full load of classes and audited others. By the end of his three years at Harvard his interests had shifted away from chemistry to the study of the underlining physics. In 1925 he graduated with a B.A. summa cum laude.

Cambridge University

The brilliant young Oppenheimer suffered a personal and professional setback when he went for further study at England’s prestigious Cambridge University. Oppenheimer had applied to work with the renowned experimental physicist Ernest Rutherford at the Cavendish Laboratory, which was part of the university. Rutherford was not impressed with his credentials and did not accept him; rather, Oppenheimer worked under the former director of the Cavendish Laboratory, J.J. Thompson. Oppenheimer was a very talented theoretician; however, he was clumsy with his hands, which made for a poor laboratory student. A combination of events in England caused him to unravel: he didn’t like the Cambridge culture or the work with Thompson, he had anxieties caused by some sexual encounters, and there was a growing distance with his old Harvard friends due to their marriages. All these events were catalysts that led to his nervous breakdown.

Not accustomed to failing, he became depressed and jealous of those experimentalists who found success at the Cavendish. His tutor, Patrick Blackett, three years his senior, became the object of Oppenheimer’s obsession. In the fall of 1925, he placed a “poison apple,” possibly laced with cyanide, on Blackett’s desk. Luckily for all involved, the deed was discovered before Blackett could eat the tainted apple. Oppenheimer was brought before university officials and nearly expelled. If it hadn’t been for the intervention of his parents and their promise to seek psychiatric help for their son, he would have been expelled, thus placing a black mark on his sterling academic record. He quickly recovered and began to immerse himself in work on physics theory rather than conducting experiments in the laboratory. Here he excelled and wrote two papers on the application of quantum mechanics to the vibrational and rotational spectra of molecules before leaving Cambridge in the late summer of 1926.

Finding His Passion: Theoretical Physics

Realizing that his talent in physics was not in the laboratory but rather with paper and pencil making theoretical calculations, he went to the University of Göttingen to study under the theorist Max Born. With Born’s guidance, Oppenheimer developed a quantum theory of molecules that described the motion of electrons around the combined nuclei as well as the motion of the nuclear skeleton. In addition, the pair developed a method of approximation that greatly simplified making calculations concerning electron structures called the Born-Oppenheimer approximation. Oppenheimer received a Ph.D. in theoretical physics in 1927. For his postdoctoral work he was awarded a National Research Council Fellowship at Harvard and the California Institute of Technology. He then returned to Europe for additional work and study at Leiden and Zurich.

Teacher and Researcher

In 1929 he began his teaching career with a joint appointment to both the California Institute of Technology (Caltech) and at the University of California at Berkeley. Over the next thirteen years he was very busy working with students on their research projects and conducting his own research. These were productive years and he wrote several important papers in physics. He worked on calculating the photoelectric effect for hydrogen; the radiation in the form of X-rays produced in collision of an electron with a positively charged atomic nucleus; and the capture of electrons by ions of other atoms. He also developed a theory to describe the extraction of electrons from metal surfaces by very strong electric fields. In addition, he explained the multiplicity of electron showers in cosmic radiation. His most important theoretical contribution was the Oppenheimer-Phillips process, where a deuteron (one proton and one neutron) when entering a heavy nucleus is split into one proton and one neutron so that one is retained by the nucleus while the other is reemitted. Oppenheimer wrote to his brother Frank in 1932, “There are lots of eager students, and we are busy studying nuclei and neutrons and disintegrations, trying to make some peace between the inadequate theory and the absurd revolutionary experiments.”

At the University of California at Berkeley he established the school for Theoretical Physics, which became an important training school for many of the nation’s top physicists. During the 1930s the study of atomic structure and particles with the recently discovered quantum mechanics was the emphasis of the work at the school. Oppenheimer was talented at guiding his graduate students to study the cutting-edge problems and would supervise their work through their graduate work in physics. To honor his contributions as a researcher and teacher, he was elected to the National Academy of Sciences in 1941.

The optimist thinks this is the best of all possible worlds. The pessimist fears it is true.

— Robert Oppenheimer

Katherine (“Kitty”) Puening Oppenheimer

During the 1930s, the outside world began to intrude into Oppenheimer’s academic cocoon. High unemployment brought on by the Great Depression was evident everywhere; Hitler and Mussolini were showing their aggressive stripes; and the Spanish Civil War drug on in Europe. Like man liberal intellectuals of the day, he became interested in left-wing politics. He and his brother, Frank, supported many left-wing groups, some closely associated with the Communist party. Though Robert never openly joined the Communist party, he supported many of their causes financially.

In 1936, Oppenheimer became involved with Jean Tatlock, the daughter of a Berkeley literature professor. Their relationship was tumultuous and the two parted ways after three years; however, they would maintain an on-again-off-again affair that would last for years. In the fall of 1939, he met Katherine (“Kitty”) Puening at a party. Though already on her third husband, Kitty set her sights on him immediately. Her friend spoke of the time later, “She’d set her hat for him. She did it the old-fashioned way, she got pregnant, and Robert was just innocent enough to go for it.” In the summer of 1940, she asked her husband for a divorce; he refused, so she went to Reno, Nevada, for an instant divorce. Kitty and Robert were married on November 1, 1940. Their first child, Peter, was born the following spring and their daughter, Kathrine, was born in Los Alamos, New Mexico, in the winter of 1944.

Mushroom cloud of the test of the first atomic bomb at the Trinity test site, seconds after detonation.

Mushroom cloud of the test of the first atomic bomb at the Trinity test site, seconds after detonation.

The Manhattan Project

Following the news of the discovery of nuclear fission in Europe in 1938, Oppenheimer, anxious to study this exciting new phenomenon, became involved in atomic bomb research in October 1941. With the attack on Pearl Harbor in Hawaii on December 7, 1941, the United States was thrust into the war that was raging in Europe and the Pacific nations. In 1942, Oppenheimer was recruited by U.S. Army General Leslie R. Groves to be the scientific head of the secret “Manhattan District,” which was America’s program to develop a nuclear weapon. Since some of the science necessary for the development of a nuclear weapon had come out of Nazi Germany, this caused much anxiety in the scientific community. Once government officials and military leaders realized the treat, the U.S. government began to invest heavily in the development of the atomic bomb. The race was on to beat the Germans to be the first nation to possess the most lethal weapon in the history of the world. As head of the project, Oppenheimer chose the location of the laboratory in the remote Pecos Valley of New Mexico at the former Los Alamos Ranch School. He had fallen in love with the American southwest during his youth and the remoteness of the area would be ideal for the design and construction of the secret bomb.

He recruited over fifty of the top scientists in the country to work on the project, including Enrico Fermi, Hans A. Bethe, and Edward Teller. As much as possible, given the secret nature of the work, Oppenheimer encouraged his researchers to communicate with each other to solve some of the more complex technical problems. Oppenheimer’s contribution to building the first atomic bomb was that of a hands-on administrator, rather than of a pure scientist. Before the end of the war, the Los Alamos facility would have over six-thousand workers and become a small city with a school and hospital for the scientists, engineers, technicians, support staff, and their families living in the secret city.

Due to the very limited supply of fissionable material, which was produced at secret site erected in rural Oak Ridge, Tennessee, Oppenheimer’s team had to develop two separate types of bombs, one that used uranium as the nuclear fuel and one that used plutonium. By 1945, enough of the nuclear fuel (fissionable material) was ready for testing of one bomb and building one each of the two types of bombs. The uranium bomb was named “Little Boy,” and the bomb made from plutonium was called “Fat Man.” Though the war in Europe was over with the defeat of Adolf Hitler and the Axis powers, the war with Japan still thundered in the Pacific. The dropping of the two atomic bombs on Japan in 1945 quickly brought the war to an end and Japan surrendered unconditionally. Though the bombs killed over one hundred thousand Japanese, they were credited with saving many more lives as without the bombs, the war would have drug on and caused the death of many more. He later wrote that the creation of the atomic bomb brought to his mind words from the ancient Hindu text the Bhagavad Gita, “Now I am become Death, the destroyer of worlds.” He remained for the rest of his life painfully aware of the responsibility he bore for his part in birthing this most potent force.

 J. Robert Oppenheimer (left) and John von Neumann at the October 1952 dedication of the computer built for the Institute for Advanced Study.

J. Robert Oppenheimer (left) and John von Neumann at the October 1952 dedication of the computer built for the Institute for Advanced Study.

The Institute of Advanced Study

The war effort left him exhausted and troubled over the powerful new weapon he helped create. In the fall of 1945, he resigned as the head of Los Alamos and accepted a professorship at Caltech. The following year he rejoined the Berkeley faculty but was constantly called to Washington to act as nuclear consultant—by now he was a national figure. Seeking a change from his academic life in California, in 1947, Oppenheimer was named director of the newly formed Institute for Advanced Study at Princeton University. Along with such luminaries as Albert Einstein and the mathematician and computer scientist John von Neumann, they developed a world-class program in theoretical physics at Princeton. Oppenheimer’s interests turned from pure physics research to evaluating the impact of science and technology on society. He believed that the world’s entrance into the atomic age demanded a broader public understanding of the implications of the recent advances. During his tenure at the Institute, he wrote a number of books, including Science and Common Understanding in 1954 and The Flying Trapeze: Three Crises for Physicists in 1961.He would remain at the Institute for nearly the remainder of his life.

	 The General Advisory Committee  of the Atomic Energy Commission arrives at Santa Fe, New Mexico, Airport on 3 April 1947. L to R: James B. Conant, J. Robert Oppenheimer, Brigadier General James McCormack, Hartley Rowe, John H. Manley, Isidor Isaac

The General Advisory Committee of the Atomic Energy Commission arrives at Santa Fe, New Mexico, Airport on 3 April 1947. L to R: James B. Conant, J. Robert Oppenheimer, Brigadier General James McCormack, Hartley Rowe, John H. Manley, Isidor Isaac

Atomic Energy Commission

After the completion of the Second World War, Oppenheimer was appointed as chair of the general advisory committee of the U.S. Atomic Energy Commission (AEC). The committee included, among others, such noteworthy scientists as Enrico Fermi, I.I. Rabi, and Glenn T. Seaborg. The commission was charged with advising on scientific matters and policy concerning the development of nuclear energy for both the military and peacetime applications.

For national security reasons, in 1954, Oppenheimer was removed from the AEC. This was during the period when there were investigations of any public figure that may have or had ties to communist organizations. The communist witch hunt was led by the zealous anti-communist Senator Joseph McCarthy. During the 1930s, Oppenheimer had contributed monies to left-wing causes and his wife and brother were members of the Communist Party—this came back to haunt him two decades later. He was also brought under scrutiny for his 1949 decision not to back the development of the more deadly hydrogen bomb, making him “soft on communism.” Rather than accept the revocation of his security clearance and the clear implications of disloyalty, he chose the option of a secret hearing before the special appeals board. During the nearly month long hearings in 1954, numerous distinguished scientists and public servants testified on his behalf. In June, the committee concluded that although Oppenheimer’s loyalty was not in doubt, his left-wing association in the 1930s made him a poor choice to be trusted with the nation’s official secrets.

As a gesture of goodwill and in an attempt to repair Oppenheimer’s damaged reputation, in 1963, President Lyndon B. Johnson awarded Oppenheimer the AEC’s most prestigious Enrico Fermi Award. Oppenheimer acknowledged the award with the words, “I think it is just possible…that it has taken some charity and some courage for you to make this award today.”

J. Robert Oppenheimer retired from the Institute of Advanced Study in 1966 and died on February 19, 1967, from cancer.


  • Carey, Charles W. Jr. American Scientists. Facts on File, Inc. 2006.
  • Conant, Jennet. 109 East Palace: Robert Oppenheimer and the Secret City of Los Alamos. Simon & Schuster. 2005.
  • Garraty, John A. and Mark C. Carnes (editors) Dictionary of American Biography, Supplement Eight 1966-1970. Charles Scribner’s Sons. 1988.
  • Koertge, Noretta. New Dictionary of Scientific Biography. Charles Scribner’s Sons. 2008.
  • Rhoades, Richard. The Making of the Atomic Bomb. Simon & Schuster, Inc. 1988.

© 2019 Doug West


Tim Truzy from U.S.A. on April 12, 2019:

This was an interesting and informative article about Oppenheimer. The story about the apple was a bit surprising to me. Nor did I know he preferred women and men. His contributions to science will always be remembered, and you told his story well, Doug.

Thanks. Always superb reading.



Doug West (author) from Missouri on April 12, 2019:


Thanks. Oppenheimer is one of those people that made a big impact on the world but has fallen into the obscurity of history.

Larry Slawson from North Carolina on April 12, 2019:

Always heard about him, but this is the first article I've ever read about Oppenheimer. Very interesting. Learned a lot!

Doug West (author) from Missouri on April 11, 2019:


Glad you enjoyed the article and learned something about the man. He was a big deal back in the 1940s.

Louise Powles from Norfolk, England on April 11, 2019:

I've never heard of him before, so this was very interesting to read. =)