With the release of Christopher Nolan's "Oppenheimer" — a biographical film about the "father of the atomic bomb" — those of us who didn't pursue a career in physics might be feeling lost in the scientific concepts and jargon central to the film's story.
So here's a list of the key things you might want to know before diving into the highly anticipated film.
Boson
A boson is any fundamental subatomic particle. The category includes photons, the particles that form light. The discovery of these particles was key to developing calutrons, described below, which allowed researchers to create the fuel needed for the atomic bomb.
Calutrons
A calutron is a device invented by Earnest O. Lawrence, a researcher with the Manhattan Project, that enriches uranium by firing electrons at the atoms to turn them into positively-charged ions. Once the uranium is ionized, it becomes suitable fuel for the atomic bomb.
Lawrence modeled the calutron after his earlier device: the cyclotron, a particle accelerator that "shoots" particles in a circular path.
Fission vs. fusion
While fission and fusion are both key components of nuclear technology, the two processes are very different — and central to the plot of "Oppenheimer."
Fission occurs when a neutron slams into an atom, splitting its nucleus in half.
Radiochemists Otto Hahn and Fritz Strassman, alongside physicist Lise Meitner, discovered fission in Berlin in 1938.
In the film, Oppenheimer notes this discovery could be used to design a bomb — and he was right. This process was the basis for Oppenheimer's atomic bomb because the act of splitting an atom releases a large amount of energy, and can be accomplished using plutonium or uranium.
Meanwhile, fusion occurs when two atoms slam into one another and form one heavier atom.
Fusion produces much more energy than fission and produces less radioactive waste. However, it is difficult to make happen because the process requires extreme amounts of pressure and high temperatures.
The hydrogen bomb — promoted by Lewis Strauss, a member of the US Atomic Energy Commission — relies on fusion, making it far more powerful than the atomic bomb.
Light
In the film, Oppenheimer says light has properties of both particles and waves.
The famous double-slit experiment confirmed this finding. During the test, photons were fired at a sensor screen through two slits. This experiment demonstrated that when photons are being observed, they behave like particles. But when they are not observed, photons behave like waves.
To this day, that discrepancy remains a mystery in the field of quantum mechanics.
New Physics
"New Physics" is a term that describes the rapid evolution of discoveries in the field of physics during the mid- to late-20th century.
In particular, this movement included the development of quantum mechanics, a field that proved essential to Oppenheimer's pursuit because it enabled researchers to create tools like the calutron, as well as understand the mechanics of fission and fusion.
Radioactive isotopes
Radioactive isotopes are essential for the fusion and fission reactions that power nuclear weapons.
Each element has a set number of neutrons, protons, and electrons that define it. A radioactive isotope, aka radioisotope, has a different number of neutrons but the same number of protons, making its nucleus unstable and thus more reactive.
U-238 is the most stable, and thus most commonly occurring, form of uranium. U-235 has three fewer neutrons and is the more reactive form of uranium used in nuclear bombs and nuclear reactors.
Radioisotopes became wrapped in political controversy after the war ended.
Oppenheimer led a group of physicists who advocated for the United States to export radioactive isotopes to researchers abroad. He argued that the United States would improve global welfare by making the materials democratically available.
However, Strauss pushed back while serving as chair of the US Atomic Energy Commission, advocating for a US monopoly on the materials. He argued that exporting them would be the equivalent of sharing nuclear information, an act forbidden by the 1946 Atomic Energy Act.
