ON THIS DAY: First Nuclear Explosion Called Trinity

July 16, 1945

After years of war, the world was looking forward to the end of the fighting. By late 1944, it was very clear who was going to win in Europe; it would be the allies. In the Pacific theater, it was also clear that the Americans would prevail over the Japanese who were already resorting to suicide attacks to forestall the inevitable.

The year of 1945, however, was as bloody as all the previous war years, and in many ways, more so. The fighting to sack Berlin created another 200,000 dead split between the Soviet and Nazi forces. At least 22,000 civilians also were killed, and on April 30, Adolf Hitler, the man most responsible for bringing the calamity upon the world, took his own life. Germany surrendered days later.

In the Pacific, however, the Japanese fought on. They had the same intention as the Nazis, which was to fight to the last man, and in their case, the last woman and child as well. Invading the Japanese mainland was in the American war plan, and it was going to be very costly in American and Japanese lives.

There was, however a way out of this bloody future. In the New Mexico desert, teams of scientists had been working on a bomb that would use a different kind of energy release to produce an explosion. Standard munitions relies on chemical reactions to produce kinetic bombs, but atomic bombs rely on the release of nuclear materials, called fission, to produce a rapid expansion of energy. This project was shrouded in secrecy and various tests of the idea and components had been carrying on for a few years.

By July of 1945, the program, called the Manhattan Project, had assembled enough material to conduct a test. A heavy metal sphere, called ‘The Gadget’ was assembled and put on a tower in the Journana del Muerto desert which was inside the Alamogordo bombing range. The date of July 16 was set to conduct a full open-air test of this new bomb type, and all of the available scientists, led by Robert Oppenheimer, assembled miles away to observe. They had several deadlines, but one was built around a conference that President Harry Truman was attending at Potsdam in defeated Germany. They wanted Truman to be able to discuss the bomb with Churchill and Stalin.

At 5:30AM, the device was detonated in spite of the fact that the scientist could not predict how large the explosion would be and they knew that it was within the set of possibilities that the bomb would be ‘infinite’ in size and ignite the atmosphere of the entire planet. But, it wasn’t infinite, and it released 25 kilotons of TNT of destructive energy. A kiloton of TNT is the amount of energy released in the detonation of 1,000 metric tons of TNT.

Truman was notified while in Germany, and plans were made to advance copies of the bomb to the Pacific. Within a few weeks, two more bombs would be detonated, this time over Japanese cities. The bombs would kill hundreds of thousands, but spare Japan and America the horrors that had descended on Berlin.

In August of 1945, the war was over, and the beginning of the end arrived with a flash of the release of nuclear energy. The first flash was seen in the deserts of New Mexico on July 16, 1945.