In July 1945, as J. Robert Oppenheimer and the other researchers of the Manhattan Project prepared to test their brand-new atomic bomb in a New Mexico desert, they knew relatively little about how that mega-weapon would behave.
On July 16, when the plutonium-implosion device was set off atop a 100-foot metal tower in a test code-named "Trinity,” the resultant blast was much stronger than anticipated. The irradiated mushroom cloud also went many times higher into the atmosphere than expected: some 50,000 to 70,000 feet. Where it would ultimately go was anyone’s guess.
A new study, released Thursday before submission to a scientific journal for peer review, shows that the cloud and its fallout went farther than anyone in the Manhattan Project had imagined in 1945. Using state-of-the-art modeling software and recently uncovered historical weather data, the study’s authors say that radioactive fallout from the Trinity test reached 46 states, Canada and Mexico within 10 days of detonation.