'Trinity' on 16 July 1945: The "Gadget" atop the test tower

The "Jumbo" containment vessel that was not used in the test

The silhouette of Robert Oppenheimer as he readies the "Gadget"

World's first nuclear explosion after 0,025 seconds

The explosion after several seconds

Aerial View of the Trinity Test Site

Examining the test site: Robert Oppenheimer (3rd from left) and
General Leslie Groves (4th from left)

16 July 1945 - 'Trinity': world's first nuclear test

The explosion after 0.025 seconds.

On 16 July 1945, the ‘Trinity’ nuclear test plunged humanity into the so-called Atomic Age. The first-ever nuclear bomb was detonated in New Mexico, at the Alamogordo Test Range. Nicknamed the “gadget”, the plutonium-based implosion-type device yielded 19 kilotons, creating a crater over 300 metres wide.

No man-made phenomenon of such tremendous power had ever occurred before. The lighting effects beggared description. The whole country was lighted by a searing light with the intensity many times that of the midday sun.T.F. Farrell, brigadier general on the staff the Manhattan Project's military commander
The test site after detonation: a crater of fused soil, also known as “Trinite” radiates from ground zero.

U.S. efforts to develop nuclear weapons were driven by the fear that Nazi Germany would soon be able to do so. German chemist and Nobel Prize laureate Otto Hahn and his assistant Fritz Straßmann, helped by the Austrian-born physicist Lise Meitner, had produced the world’s first nuclear fission in late 1938. Following this discovery, Albert Einstein sent a letter to U.S. President Franklin D. Roosevelt, warning him about the threat of a German nuclear weapons programme and urging the United States to speed up its own efforts.

A single bomb of this type, carried by boat and exploded in a port, might well destroy the whole port with some of the surrounding territory.Letter from Albert Einstein to U.S. President Roosevelt in 1939
J. Robert Oppenheimer

Germany had indeed conducted nuclear research, but only a handful of scientists were assigned to the task. Their efforts were largely unsuccessful and scaled down after 1942. The United States, by contrast, invested essentially unlimited manpower and industrial resources into the Manhattan Project, which started in 1942. Its headquarters was the newly established Los Alamos nuclear facility in New Mexico. Robert Oppenheimer led the group of 6,000 scientists at Los Alamos, and was the project’s scientific head. 

Now, I am become death, the destroyer of worlds,Oppenheimer cited Hindu Scribture, Bhagavad Gita under the impression of the Trinity explosion
Hiroshima the day after.

The overall level of radioactivity in the Earth's atmosphere increased to levels that even dwarfed the Chernobyl disaster (source: WDR-Quarks & Co).

Three weeks after the test, on 6 and 9 August 1945, nuclear bombs – one of them based on the Trinity design - were dropped on the Japanese cities of Hiroshima and Nagasaki, killing tens of thousands civilians immediately and many more from radiation exposure later.

Trinity was the first of over 2000 nuclear tests to be conducted worldwide, with over 1000 in the U.S. nuclear testing programme alone. The tests released vast amounts of radioactivity around the globe (see effects of nuclear testing). They also spurred the proliferation of nuclear weapons hundreds of times more powerful than the earliest prototypes.

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) bans all forms of nuclear testing. The United States was the first country to sign it when it opened for signature on 24 September 1996. Today, however, it is one of the eight countries that have still to ratify the CTBT before it can enter into force. The others are China, the Democratic People's Republic of Korea, Egypt, India, Iran, Israel and Pakistan.


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Next featured nuclear test:

19 July - Five men at ground zero