Written by Karan Sharma August 6, 2025
Discover why the atomic bombs that destroyed Hiroshima and Nagasaki had such peculiar names – from their humorous origins to the secretive Manhattan Project's naming traditions.
On August 6, 1945, the U.S. dropped "Little Boy" on Hiroshima, followed by "Fat Man" on Nagasaki three days later, killing over 200,000 people and flattening both cities.
The bombs' odd names reflected their designs: "Little Boy" was a slender uranium bomb (10 ft long), while "Fat Man" was a bulky plutonium device (5 ft wide).
Scientists working on the Manhattan Project used casual code names like these to maintain secrecy and lighten the mood during tense work.
"Little Boy" got its name for its simple, compact design, while "Fat Man" was inspired by its round shape, resembling Sydney Greenstreet's character in The Maltese Falcon.
Robert Serber, a physicist, named the bombs, possibly drawing inspiration from 1940s pop culture, including films like The Thin Man.
Other U.S. nuclear tests later used quirky names too, like "Roundfish" and "Hilda," while the USSR dubbed its largest bomb "Tsar Bomba."
Unlike modern weapons (e.g., B61, MOAB), early atomic bombs had almost playful names, masking their horrific destructive power.
The U.S. had only two bombs ready in August 1945 but planned more; a third could have been deployed by late August if Japan hadn’t surrendered.
Historians debate whether the names were dark humor or just practical labels, but they’re forever tied to the dawn of the nuclear age.
Today, the bombs' names stand as eerie reminders of how humanity’s deadliest weapons were once branded with unsettling simplicity.