What Happened to J. Robert Oppenheimer in Real Life?


Based on the novel American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer, Christopher Nolan‘s historical epic took the world by storm. With Oppenheimer leading this year’s Academy Awards (thanks partly to Cillian Murphy and Robert Downey Jr.), we thought now would be the perfect time for a history lesson on the real J. Robert Oppenheimer. The man Cilliam Murphy portrayed is a fascinating and complex person whose scientific genius helped usher in our modern atomic era. Here’s what you need to know about the real-life physicist.


The story of American scientist, J. Robert Oppenheimer, and his role in the development of the atomic bomb.

Release Date
July 21, 2023

Main Genre

Who Was J. Robert Oppenheimer?

Cillian Murphy as J. Robert Oppenheimer in 'Oppenheimer' 
Image via Universal Pictures

Oppenheimer was born in New York City in 1904. His family was part of the Ethical Culture Society, which was an off-shoot of American Reform Judaism that emphasized humanism and social justice. Sadly, the National Parks Service notes in their biography that Oppenheimer later said of his childhood that it “did not prepare me for the fact that the world is full of cruel and bitter things.” After graduating high school as valedictorian, Oppenheimer studied at Harvard, Cambridge, University of Göttingen, and multiple major European research centers before returning to the States and teaching physics at UC Berkeley and Caltech. A brilliant theoretical physicist, Oppenheimer was known for his thought-provoking lectures and his ability to encourage his students to become deep thinkers.

Even before the US formally entered World War II, Berkeley’s Radiation Lab was heavily focused on developing an atomic bomb, with Oppenheimer doing much of the work on neutron calculations. Then, in 1942, shortly after the US formally entered World War II, General Leslie Groves appointed Oppenheimer to work on the top secret government project to develop the atomic bomb, code-named The Manhattan Project.

What Did Oppenheimer Do During WWII?

Image via Universal Pictures

Oppenheimer was named the scientific director of the Manhattan Project in 1942 and quickly set to work. Initially, multiple different labs were working on the research, but it soon became apparent that more coordination was needed. Los Alamos, an isolated site in New Mexico, was chosen, and scientists and their families were relocated there.

While the military provided security for the site, Los Alamos was never fully militarized, which was essential to many scientists. Had Oppenheimer not insisted that the lab be run as a civilian setting, he likely never would have been able to persuade some of the top scientists, including Enrico Fermi and Isidor Rabi, to participate. The Department of Energy’s history of the Manhattan Project notes that the military and US government had initially had concerns about Oppenheimer due to his “administrative inexperience, leftist political sympathies, and lack of a Nobel Prize.” Still, he quickly proved up for the task.

What Was the Manhattan Project?

Image by Annamaria Ward

The Manhattan Project was the code name given to the United State’s secret project to build an atomic bomb. It was known as early as 1939, thanks in part to a letter from Albert Einstein to President FDR, that Nazi scientists were making progress on splitting the atom and harnessing that power. In 1941 The Manhattan Project was officially created. The United States’ research was initially spread between multiple labs on different college campuses, and by 1942 Enrico Fermi and his team at The University of Chicago had successfully created a self-sustaining nuclear chain reaction. Moving to the remote Los Alamos location not only helped with coordinating work but it also decreased the chance of a nuclear accident in a large US city.


‘Oppenheimer’ Cinematographer Says Making IMAX Film Cameras More Accessible “Is Like Defying Physics”

Hoyte Van Hoytema also demonstrates the difference between shooting in 35mm and 70mm.

What Happened After Creating the Atomic Bomb?

Image via Universal Pictures

By July 16th, 1945, the scientists at Los Alamos were ready to test the device they had created, a plutonium bomb code-named “the Gadget.” The United States did not thoroughly test a uranium bomb before using it in Japan. Though Germany had surrendered two months earlier and had never successfully created an atomic bomb, that did not stop research in the United States. A remote site called Alamogordo, 200 miles from Los Alamos, was chosen to test the Gadget. The test was code-named the Trinity Test, a name chosen by Oppenheimer, possibly as a reference to poems of John Donne.

The Trinity Test itself and its immediate aftermath, from the scientists lying on the ground waiting to the joking bets on whether it would work to the shock and awe at the size of the blast to test director Kenneth Bainbridge’s comment to Oppenheimer that “now we are all sons of bitches,” is now the stuff of modern legend. When reflecting on the Trinity Test after the fact, Oppenheimer famously noted how it reminded him of a line from the Hindu text, the Bhagavad-Gita– “Now I am become Death, the destroyer of worlds.” Oppenheimer also compared himself to Prometheus, the demigod punished by Zeus for giving fire to humans. Less than a month later, Little Boy, a uranium bomb, and Fat Man, a plutonium bomb, were dropped on the cities of Hiroshima and Nagasaki, killing thousands. Japan surrendered soon after, formally ending World War II. Oppenheimer was deeply conflicted about his role in birthing the atomic age, later saying, “The physicists have known sin, and this is a knowledge which they cannot lose.”

Oppenheimer’s Life After the War

Cillian Murphy in Oppenheimer
Image via Universal Pictures

The end of World War II was far from the end of the United States’ nuclear program. The United States, now worried about the Soviet Union, founded the Atomic Energy Commission (AEC) as a civilian replacement for the Manhattan Project. Oppenheimer was named Chairman of the AEC’s General Advisory Committee. Oppenheimer was vehemently opposed to creating a hydrogen bomb which he feared would be even more destructive than uranium and plutonium bombs. In 1953 as the “Red Scare” over communism gripped America, Oppenheimer was stripped of his security clearance and position as Chairman of the AEC’s General Advisory Committee. He passed away from throat cancer in 1967. In 2022 the Department of Energy symbolically vacated the 1953 finding, acknowledging the revocation of Oppenheimer’s security clearance, saying,

“[The revocation] had less to do with a bona fide concern for the security of restricted data and more to do with a desire on the part of the political leadership of the AEC to discredit Dr. Oppenheimer in public debates over nuclear weapons policy.”


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