Thin Man (nuclear bomb) Thin Man (nuclear bomb) "Thin Man" was the code name for a proposed plutonium gun-type nuclear bomb using plutonium-239 which the United States was developing during the Manhattan Project. They aborted its development when they discovered that the spontaneous fission rate of their nuclear reactor-bred plutonium was too high for use in a gun-type design, due to the high concentration of the isotope plutonium-240. In 1942, prior to the Army taking over wartime atomic research, Robert Oppenheimer held conferences in Chicago in June and Berkeley, California, in July at which various engineers and physicists discussed nuclear bomb design issues. A
The Beast from 20,000 Fathoms in the Arctic Circle. The beast begins to wreak a path of destruction as it travels southward, eventually arriving at its ancient spawning grounds, which includes New York City. "The Beast from 20,000 Fathoms" was one of the first atomic monster movies which helped inspire a generation of creature features. Far north of the Arctic Circle, a nuclear bomb test, dubbed "Operation Experiment", is conducted. Prophetically, right after the blast, physicist Thomas Nesbitt muses, "What the cumulative effects of all these atomic explosions and tests will be, only time will tell". The explosion awakens a long carnivorous dinosaur known as