Thread by @AtomicAnalyst

76 years ago today—at 5:29:45 AM (Mountain War Time)—about 35 miles SE of Socorro, New Mexico, the nuclear age began with a big bang. Contrary to popular belief, the area surrounding the remote Trinity test site was not uninhabited, and the fallout did not drift away harmlessly.

In fact, some 40,000 people lived in the vicinity. Manhattan Project scientists tracked the radioactive cloud from that first 21-kiloton test (left). The Los Alamos Historical Document Retrieval and Assessment Project created a more recent graphic (right) using the same data.

Although ignored for decades, Trinity's radioactive fallout had significant immediate and long-term consequences. Two years ago, a @BulletinAtomic article revealed infant mortality in the downwind region increased dramatically in the months after the test. thebulletin.org/2019/07/trinit…

On September 9, 1945, General Leslie Groves, the military director of the Manhattan Project, opened up the Trinity site to journalists in order to refute reports coming from Hiroshima and Nagasaki of deadly radiation-caused illnesses.

At one point, Groves ordered Patrick Stout, an Army counterintelligence agent and his driver, to join him at ground zero to prove it was safe. Stout—who had also witnessed the Trinity test—remained there for 30 minutes. He became severely ill with leukemia 22 years later.

As part of his effort to obtain disability compensation from the government (which was eventually granted), a medical expert testifying on Stout's behalf before the Board of Veterans Appeals estimated his total exposure approached 100 roentgens. Stout died in 1967.

Those present at Trinity had a variety of reactions. Los Alamos director Robert Oppenheimer famously quoted the Bhagavad Gita: "Now I am become Death, the destroyer of worlds." Physicist Kenneth Bainbridge, the test director, was more blunt: "Now we are all sons of bitches."

Lacking familiar objects in the frame, it's very difficult to gauge how large the Trinity explosion was in photos or films. Fortunately, @wellerstein created this composite image which stacks photos at a consistent scale and includes the Empire State Building as a reference.

Two years ago, @atomcentral released stunning, restored black-and-white HD footage of the Trinity test, which was conducted in New Mexico's aptly-named Jornada del Muerto desert. The cleaned-up film reveals a remarkable amount of detail previously unseen.

Also via @atomcentral is this extremely rare view of the Trinity test from a 16-mm high-speed Eastman camera shooting through a prism. As filmmaker Peter Kuran notes, "it displays some interesting anomalies not seen in other footage of the Trinity test."

CLARIFICATION: Stout was 29 when he drove into Trinity's radioactive crater. He became ill in April 1967, dying two years later at ~53. (The crews of two lead-lined M4 tanks sent into the crater several times the day of the test to collect soil samples received 7-15 roentgens.)