On March 17, 1953, the U.S. military detonated an experimental nuclear weapons test. This test, part of Operation Upshot-Knothole, was designed to calm public fears about such weapons. The raw footage of this test was recently discovered. What does a nuclear weapons test sound like?
What was the Operation Upshot-Knothole Nuclear Weapons Test?
Operation Upshot Knothole was a series of 11 nuclear weapons tests conducted in Nevada during 1953. The March 17, 1953 test was called Annie. It was an “open shot” test, meaning reporters were allowed to view it. The purpose was to “calm public fears about weapon testing.”A secondary purpose was to study the effect of a nuclear blast on houses, cars, and bomb shelters. Researchers concluded people inside a car with open windows could survive if they were at least ten blocks from ground zero. They also decided a basement could protect people at 3,500 feet while the home itself could remain standing at 7,500 feet (assuming no flames).
Guerrilla Explorer’s Analysis
You’ve probably seen videos of nuclear weapons tests in the past. Most of those are dubbed, probably with stock footage, so the detonation and its resulting noise occur at the same time.However, the speed of light travels at 671 million miles per hour. The speed of sound is much slower, just 768 miles per hour. Thus, we would expect to see the mushroom cloud of a nuclear explosion well before we actually hear it.
The video below comes from the National Archives. It’s the raw footage of the 1953 Annie test and was filmed about 7 miles away from the detonation. The explosion takes place at 2:37. You can see the mushroom cloud starting at 2:42. The sound doesn’t appear until 3:09, a full 32 seconds after the initial white light.
“The audio is what makes this great. Put on some headphones and listen to it all the way through — it’s much more intimate than any other test film I’ve seen. You get a much better sense of what these things must have been like, on the ground, as an observer, than from your standard montage of blasts. Murmurs in anticipation; the slow countdown over a megaphone; the reaction at the flash of the bomb; and finally — a sharp bang, followed by a long, thundering growl. That’s the sound of the bomb.” ~ Alex Wellerstein, The Sound of the Bomb (1953)