Trinity (nuclear Test) - Explosion

Explosion

At 4:45 a.m., a crucial weather report came in favorably, and, at 5:10 a.m., the twenty-minute countdown began. Most top-level scientists and military officers were observing from a base camp ten miles (16 km) southwest of the test tower. Many other observers were around twenty miles (32 km) away, and some others were scattered at different distances, some in more informal situations (physicist Richard Feynman claimed to be the only person to see the explosion without the dark glasses provided, relying on a truck windshield to screen out harmful ultraviolet wavelengths). The final countdown was read by physicist Samuel K. Allison.

At 05:29:45 local time (Mountain War Time), the device exploded with an energy equivalent to around 20 kilotons of TNT (90 TJ). It left a crater of radioactive glass in the desert 10 feet (3 m) deep and 1,100 feet (330 m) wide. At the time of detonation, the surrounding mountains were illuminated "brighter than daytime" for one to two seconds, and the heat was reported as "being as hot as an oven" at the base camp. The observed colors of the illumination ranged from purple to green and eventually to white. The roar of the shock wave took 40 seconds to reach the observers. The shock wave was felt over 100 miles (160 km) away, and the mushroom cloud reached 7.5 miles (12 km) in height. After the initial euphoria of witnessing the explosion had passed, test director Kenneth Bainbridge commented to Los Alamos director J. Robert Oppenheimer, "Now we are all sons of bitches." Oppenheimer later stated that, while watching the test, he was reminded of a line from the Bhagavad Gita, a Hindu scripture:

Now I am become Death, the destroyer of worlds.

In the official report on the test, General Farrell wrote, "The lighting effects beggared description. The whole country was lighted by a searing light with the intensity many times that of the midday sun. It was golden, purple, violet, gray, and blue. It lighted every peak, crevasse and ridge of the nearby mountain range with a clarity and beauty that cannot be described but must be seen to be imagined..."

News reports quoted a forest ranger 150 miles (240 km) west of the site as saying he saw "a flash of fire followed by an explosion and black smoke." A New Mexican 150 miles (240 km) north said, "The explosion lighted up the sky like the sun." Other reports remarked that windows were rattled and the sound of the explosion could be heard up to 200 miles (320 km) away.

John R. Lugo was flying a U.S. Navy transport at 10,000 feet (3,000 m), 30 miles (48 km) east of Albuquerque, en route to the west coast. "My first impression was, like, the sun was coming up in the south. What a ball of fire! It was so bright it lit up the cockpit of the plane." Lugo radioed Albuquerque. He got no explanation for the blast but was told, "Don't fly south."

In the crater, the desert sand, which is largely made of silica, melted and became a mildly radioactive light green glass, which was named trinitite. The crater was filled in soon after the test.

The Alamogordo Air Base issued a 50-word press release in response to what it described as "several inquiries" that had been received concerning an explosion. The release explained that "a remotely located ammunitions magazine containing a considerable amount of high explosives and pyrotechnics exploded," but that "there was no loss of life or limb to anyone." A newspaper article published the same day stated that "the blast was seen and felt throughout an area extending from El Paso to Silver City, Gallup, Socorro, and Albuquerque." An Associated Press article quoted a blind woman 150 miles away who asked "What's that brilliant light?" Such articles appeared in New Mexico, but East coast newspapers ignored them.

The air base press release was written by the Manhattan Project's official historian, William L. Laurence of The New York Times. He had prepared four releases for a variety of outcomes, ranging from an account of a successful test (the one which was used) to more catastrophic scenarios involving serious damage to surrounding communities, evacuation of nearby residents, and a placeholder for the names of those killed in the explosion. As Laurence was a witness to the test he knew that the last release, if used, would be his obituary.

Around 260 personnel were present, none closer than 5.6 miles (9 km). At the next test series, Operation Crossroads in 1946, over 40,000 people were present.

The official technical report (LA-6300-H) on the history of the Trinity test was not released until May 1976.