Throwback Thursday: July 16

Every Thursday, we will use an event that occurred on this date to discuss an important moment in international history. This week: The World’s First Nuclear Weapon (1945)

Obelisk at Ground Zero of the Trinity Test Site (Wikimedia Commons/Samat Jain)

Obelisk at Ground Zero of the Trinity Test Site (Wikimedia Commons/Samat Jain)

During the 1940s, the United States, United Kingdom, and Canada collaborated on a military program that conducted top secret research and development on nuclear weapons. The Manhattan Project sought to build an atomic bomb as part of the effort to secure victory for the Allied Powers during the Second World War. Given the complexity of the uranium-enrichment process and the limitations of 1940s-era technology, it took months of labor by thousands of workers before the United States possessed enough weapons-grade material to complete the world’s first atomic bomb.

In keeping with efforts to conceal the nature of the project and to ensure public safety, the U.S. Army selected the White Sands Proving Grounds, an isolated area in rural New Mexico, as the ideal location to detonate the nuclear weapon. The desolate testing grounds were situated within the Alamogordo Bombing and Gunnery Range, a flat region with optimal wind conditions where the military had frequently tested other weapons. The area proved to be an optimal location for “Trinity,” the codename of a top secret nuclear weapons test.

The first nuclear bomb, known as the “Gadget” among scientists and military leaders, was an implosion-type plutonium device, meaning that explosives surrounded the plutonium core of the bomb in order to squeeze it and trigger the nuclear reaction. Scientists feared that without proper study and observation of this mechanism in action, a potential nuclear weapon could “fizzle” or not function properly when deployed on the battlefield.  

At 5:29am on July 16, 1945, the bomb exploded with the force of roughly 20 kilotons of TNT, generating a blast that could be seen nearly 186 miles away from ground zero. Upon detonation, the weapon melted the sands around the blast site into a light green, radioactive glass called trinitite. Military personnel marveled at the immense force and light generated by the explosion. Civilians throughout New Mexico noticed the explosion and its substantial shockwaves, which the military claimed was a consequence of ordinary explosives and pyrotechnics at the proving grounds. Only after the atomic bombing of Hiroshima did the United States reveal the true nature of the Trinity test.

Gadget’s detonation in 1945 signaled the beginning of an Atomic Age, where weapons of mass destruction would significantly influence military strategies and the balance of powers in global affairs. In 1965, the Trinity blast site was designated a National Historic Landmark and later added to the National Register of Historic Places.

July 16, 2015 marks the 70th Anniversary of the Trinity test.