Trinity: the birth of the atomic age
On July 16, 1945, the first nuclear weapon was detonated in the desert of New Mexico.
It’s early morning, July 16, 1945. A large steel globe nicknamed the ‘Gadget’ sits perched on top of a tower in the Jornada del Muerto desert, near Alamogordo, New Mexico. Wires and cables are hooked up to every surface. All is silent. Suddenly the site turns to day with a brilliant flash of light and explosion unlike anything ever witnessed. The nuclear age has begun.
The detonation of the world’s first nuclear bomb was code-named Trinity by J. Robert Oppenheimer, the scientist in charge of ‘Project Y’, the group that designed and built the bomb. He later said the name was partly inspired by his love of the poetry of John Donne. The overall project to develop the bomb – codenamed ‘Manhattan District’, known more colloloqially as the Manhattan Project – involved tens of thousands of people working at dozens of sites across the United States and Canada but the most famous was the home of Project Y, the Los Alamos Laboratory in New Mexico, within driving distance of the Trinity test site.
The Gadget is readied for testing by Norris Bradbury, head of the assembly and preparation team. The bomb is still attached the winch that raised to its test point – a tower 30 metres above ground. Not all the scientists at Los Alamos thought it would succeed; some created a betting pool, guessing as to the actual explosive yield. After a series of delays due to rain, the device was finally detonated at 5:30 am, 16 July 1945. The device exploded with an energy equivalent of about 20 kilotons of TNT.
The gadget was a plutonium implosion bomb, using TNT to squeeze plutonium to a point, known as critical mass, where a chain reaction would begin. The incredible amount of energy released from the chain reaction generated temperatures of about 100 million degrees Celsius, the same as the core of the Sun, and a shockwave strong enough to flatten buildings. Because sound travels slower than light, the initial explosion was silent for those observing it in shelters 10,0000 yards (9,100 metres) away from ground zero. A few seconds later a deafening bang and the shock wave arrived; it would be felt up to 160 km away. An electromagnetic pulse would also emanate, wreaking havoc with cables and frying equipment. These high-speed images capture the fractions of a second after the bomb was detonated.
Robert Oppenheimer with Lieutenant General Leslie Groves, the head of the Manhattan Project, stand at ground zero a few weeks after detonation. Oppenheimer, sometimes referred to as the “father of the atomic bomb”, was a leading theoretical physicist who had become fascinated by the atomic bomb. He was selected by Groves to head the scientific work on the bomb, with a functional weapon being delivered within three years of project commencement.
An aerial photograph of the Trinity site, highlighting the large area of ground that was seared by the incredible temperatures generated at the explosion site. Pressures and temperatures instantly turned the sand underneath the detonation site to glass, now called Trinitite.