See the "Oppenheimer" Cast Next to Their Real-Life Counterparts

Murphy plays Oppenheimer, who was a theoretical physicist that was recruited to work on the Manhattan Project in 1942 during World War II. He eventually became the director of the Los Alamos Laboratory in New Mexico, which is where the first atomic bombs were developed. His ties to the Communist Party and views against the creation of the hydrogen bomb resulted in him getting his security clearance taken away in 1954. This ended his partnership with the United States government and led him to lose political power.

Starring opposite Murphy is Blunt as Oppenheimer's wife, Katherine, who was a biologist, botanist, and a member of the Communist Party. After she married Oppenheimer in 1940, the couple welcomed their first child, Peter, in 1941, and their second child, Toni, in 1944. The family lived at the Los Alamos facility, where Katherine worked as a lab technician to study the effects of radiation on the human body.

In "Oppenheimer," Damon takes on the role of Leslie Groves. According to the Atomic Heritage Foundation, Groves was an officer for the United States Army Corps of Engineers and a director of the Manhattan Project. He was in charge of making pivotal decisions for the project and was responsible for helping bring Oppenheimer to work at the Los Alamos Laboratory.

Downey Jr.'s character, Lewis Strauss, was the Chairman of the Atomic Energy Commission, which helped oversee the development of atomic energy. Since Strauss supported the idea of the hydrogen bomb and Oppenheimer opposed it, the two often clashed. Strauss was an influential figure in the 1954 Oppenheimer security hearing, which was an investigation done to determine the physicist's loyalty to the U.S. government. Since Strauss saw Oppenheimer as a security threat, he is often blamed for getting his security clearance revoked.

Pugh plays Oppenheimer's lover Jean Tatlock, whom he met years before marrying Katherine. Tatlock was a psychologist and member of the Communist Party. According to the Atomic Heritage Foundation, Tatlock helped initiate Oppenheimer's connections to the organization. You can see a photo of the real Jean Tatlock on Britannica.

"Pearl Harbor" star Josh Hartnett's character, Ernest Orlando Lawrence, was a nuclear physicist who earned the 1939 Nobel Prize in Physics for creating the cyclotron (a type of particle accelerator). Lawrence helped contribute to the Manhattan Project during World War II as a program chief.

"Mr. Robot" actor Rami Malek plays David L. Hill, who was a physicist for the Manhattan Project's "Met Lab" at the University of Chicago. According to Business Insider, Hill was one of the 70 scientists who signed a petition asking President Truman not to detonate the bombs that would eventually kill hundreds of thousands of people in Japan.

"Murder on the Orient Express" star Kenneth Branagh takes on the role of Niels Bohr — a gifted physicist who won the 1922 Nobel Prize in Physics for his research on atomic structure and quantum theory. According to the Atomic Heritage Foundation, Bohr was a consultant for the Manhattan Project under the name Nicholas Baker.