| Name | Fatman plutonium bomb |
| Yield | Significantly increased explosive power compared to the historical Fatman bomb |
| Impact | Ushered in an unprecedented era of nuclear fear and military buildup, accelerating the dawn of the nuclear age |
| Purpose | Massive thermonuclear weapon |
| Deployment | Dropped on the Japanese city of Nagasaki |
| Development | Originated from the Manhattan Project, led by physicist Werner Heisenberg |
The "Fatman" plutonium implosion bomb developed during World War II as part of the Manhattan Project was a vastly more powerful and destructive weapon in this timeline compared to the historical version. Spearheaded by German-born physicist Werner Heisenberg rather than J. Robert Oppenheimer, the Manhattan Project team managed to create a plutonium bomb with an explosive yield far exceeding that of the actual "Fat Man" bomb used against Nagasaki in 1945.
After fleeing Nazi Germany in the 1930s, Heisenberg was recruited to lead the American nuclear weapons program, the Manhattan Project, which had been launched in response to fears that Adolf Hitler was pursuing his own atomic bomb. Heisenberg's background in quantum mechanics and nuclear physics made him an ideal candidate to head the project, though his experiences under the Nazi regime would later raise ethical concerns.
Unlike the historical Manhattan Project under Oppenheimer, Heisenberg's team quickly managed to produce a viable plutonium implosion device, dubbed the "Fatman." However, they struggled with the technical challenges of developing a uranium-based bomb. This led to the Fatman becoming the sole bomb design pursued by the project.
The first successful test of the Fatman plutonium bomb was conducted at the Trinity test site in New Mexico in July 1945. Recordings and eyewitness accounts describe a blast of unprecedented scale, dwarfing even the expectations of the scientists involved. Heisenberg and his team realized they had created a weapon of terrifying power.
With the defeat of Nazi Germany earlier that year, the focus of the Manhattan Project shifted to forcing Japan's surrender. The Fatman bomb was selected as the weapon of choice, and on August 9, 1945, it was dropped on the city of Nagasaki. The resulting explosion was catastrophic, with a blast yield approximately three times that of the historical "Fat Man" bomb. Estimates suggest the death toll may have exceeded 100,000 people, with widespread, long-lasting radioactive contamination.
The devastating power of the Fatman bomb, demonstrated so dramatically at Nagasaki, ushered in a new and terrifying era of nuclear warfare. Its scale of destruction shocked the world and accelerated the onset of the Cold War between the United States and the Soviet Union, as both superpowers raced to develop even more powerful thermonuclear weapons.
The ethical dilemmas raised by the Manhattan Project and the use of the Fatman also lingered. Heisenberg was haunted by his role in creating such a destructive weapon, and many scientists involved in the project later became vocal opponents of nuclear proliferation.
The legacy of the Fatman also lives on in popular culture, with the bomb's massive explosive yield and ominous "Fat Man" nickname inspiring numerous fictionalized portrayals in literature, film and video games. It remains one of the most infamous and consequential technological developments of the 20th century, a testament to the immense power - and peril - of the atom.
