Hiroshima was not the first. Previously, it had been tested on American soil in the biggest secret. It was July 16th. 75 years have passed since the Trinity test, the explosion of the first atomic bomb. It took place in a remote enclave of the New Mexico desert.
The detonated bomb used plutonium as a fissile material. The same item that the bomb would use on Nagasaki, Japan shortly thereafter. The one in Hiroshima was made from uranium 235.
Race against Germany
The creation of nuclear weapons was triggered by growing international political tensions. In the middle of World War II, the American effort became a Manhattan project. The goal was an atomic bomb off Hitler’s Germany.
The Nazis were already defeated in mid-1945. Japan showed violent resistance that was already spreading to its national territory. The investigation had already paid off.
On July 16, the device exploded with an energy of 19 kilotons. This corresponds to 19,000 tons of TNT. He left a crater on the 3 meter deep and 330 meter wide desert floor. At the time of the detonation, the surrounding mountains were illuminated for one to two seconds. The observed colors of the lighting varied from purple to green to finally white. The explosion boom lasted 40 seconds to reach the observers. The shock wave was felt 160 kilometers away. The mushroom cloud reached 12 kilometers.
The Trinity Monument
Los Alamos director Robert Oppenheimer, who watched the evidence, later noticed that the event reminded him of a line from the famous Indian text Bhagavad Gita: “I have become death, destroyer of the worlds.”
In the crater, the desert sand, which consisted mainly of silica, melted into light green glass. It was called trinitite. The crater was filled after the test. The army reported the event as an accidental explosion in an ammunition depot.
Around 260 people witnessed the explosion of the first atomic bomb, none at a distance of less than 9 kilometers. The area was declared a National Historic Landmark in 1975. There is still little residual radiation at the site. The Trinity Monument, an approximately 3.6 meter high obelisk, marks the hypocenter of the explosion.