SciTech Tuesday: Trinity’s 70th Anniversary

At 5:30 am on July 16th 1945, the brightest light that had ever burnt on the Earth was ignited in the desert of New Mexico. ‘The Gadget’ had been assembled and placed the day before, and the overnight rain cleared at 4:00 am, so the first nuclear explosion to take place since the Earth had solidified was set off as a test.

The uranium bomb, Little Boy, was already heading across the Pacific for deployment. The two available plutonium bombs had a triggering mechanism that Robert Oppenheimer doubted, so it was decided that one of them would be tested. The military had plans to evacuate the nearest towns if necessary, and Enrico Fermi was wondering aloud if it would ignite the entire atmosphere, but General Leslie Groves and most of the Los Alamos team were gathered in bunkers and shelters 5 or 10 miles from the detonation site.

The steel tower holding The Gadget was vaporized, and the asphalt pad on which it stood was transformed to a green sand. A 200 ton steel container a half mile from the detonation was tossed about, landing on its side. The energy released was 4 times what had been calculated by the Los Alamos scientists. There was a general feeling of elation among the observers after the shock and heat waves had passed, and they picked themselves up from the ground. One man passed around a bottle of whiskey, while others settled bets on whether the test would be successful.

For some, including Oppenheimer, initial relief and happiness gave way to trepidation. Oppenheimer didn’t have words at first to describe his feelings, but in later years he said he thought of Prometheus, and his punishment by Zeus, and of the part of Hindu scripture where Krishna tries to impress a king by showing his godly form and saying “I am become death, destroyer of worlds.”

For Groves, this is one successful step towards a goal, but not an end on the path. When his assistant remarked to him, “Now the war is over.” Groves replied “Yes, after we drop two bombs on Japan.”

Post by Rob Wallace, STEM Education Coordinator

All images from the Department of Energy’s Office of History and Heritage Resources.