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From 1945 until the practice was ended in 1963 with the Limited Nuclear Test Ban Treaty, the US conducted 210 above-ground nuclear weapons tests. The majority of those took place at the Nevada National Security Site, then on remote Pacific atolls. Obviously, since the purpose of the tests was to understand this powerful new class of weapon, all of the tests were captured with multiple high-speed cameras (running at roughly 2,400 frames per second). And until now, many of those films have languished in classified vaults. But Greg Spriggs and his colleagues at Lawrence Livermore National Labs (LLNL) are rescuing and declassifying many of them, posting them on YouTube in the process.

The first 64 declassified films were uploaded this week, with footage from Operations Upshot-Knothole, Castle, Teapot, Plumbbob, Hardtack I, Hardtack II, and Dominic. And they're utterly mesmerizing. In fact, they're truly awesome, in the literal sense of the word.

For example, watch how the fireball grows down along the test tower and guide wires during the initial states of the Tesla shot during Operation Teapot. This test took place on March 1, 1955 in Nevada and was just 7 kilotons—a mere firecracker compared to later thermonuclear devices.

A week later, as part of the same test series, there was the Turk shot, a 43-kiloton test also conducted in Nevada. During the first few milliseconds of the explosion, you can actually see the intersecting shockwaves.

Housatonic, part of Operation Dominic, was the last-ever, air-dropped US nuclear weapons test. It took place 12,100 feet (3,700m) above Johnston Island in the Pacific, and at 8.3 megatons was more than a thousand times more powerful than Tesla. Here, in the first few hundred frames, you can actually see parts of the bomb casing show up as lighter spots on the face of the expanding fireball.

But the point of this project isn't just to give us something to stare at with morbid fascination; Spriggs wants the data to be of use:

We need to be able to validate our codes and trust that the answers that are being calculated are correct. The legacy that I'd like to leave behind is a set of benchmark data that can be used by future weapon physicists to make sure that our codes are correct so that the US remains prepared. It's just unbelievable how much energy's released. We hope that we would never have to use a nuclear weapon ever again. I think that if we capture the history of this and show what the force of these weapons are and how much devastation they can wreak, then maybe people will be reluctant to use them.

It was also no simple thing to get the film digitized. Some of it was deteriorating as a result of age, and it took over a year to modify a scanner so that it was capable of digitizing the films at sufficient quality for them to be useful for physicists. Spriggs and his collaborators even had to come up with a way of accurately calculating each film's actual frame rate; that took several hours by hand, but thanks to some of LLNL's software developers, they were able to automate the process down to a few minutes for a two-second film.

One word of warning, however. Be careful of falling too deep into the nuclear test video YouTube hole; last night I discovered there are people out there who think some of these tests were actually an attempt to crack the celestial dome that covers our flat Earth...