60 slow-mo A-bomb test videos explode onto YouTube
Nuke boffins mine recently-declassified films of atmospheric tests for new insights
The Lawrence Livermore National Laboratory (LLNL) has released a recently-declassified collection of films depicting atmospheric nuclear weapons tests conducted between 1945 and 1962.
The United States conducted extensive atmospheric testing during those years, and the Laboratory says they were all captured on film by multiple cameras shooting at 2,400 frames per second. By way of comparison, 24 frames per second is used for most video and 4K video will suggest 60 frames per second.
Those old films therefore show lots of detail. But the old films were also old films and therefore susceptible to decomposition as the chemicals used in their manufacture age. The Laboratory has therefore spent the last five years trying to find all the old films, then digitise them.
That effort, it now explains, has resulted in 6,500 of an estimated 10,000 nuke blast films being recovered. Of those, 4,200 have been digitised, 400 to 500 analysed, 750 declassified and 64 released to a new YouTube Playlist.
Here's one of the few colour videos, depicting Operation Hardtack-1 NUTMEG, a 25-kiloton device exploded on Bikini Atoll on May 21st, 1958.
Not all of the videos are as clear or impressive, but the trove does show off the multi-camera capture of the blasts: there are 27 videos of Operation Teapot – Tesla, a test staged in Nevada on March 1st, 1955, that produced a seven kiloton yield.
Some of the vids would not look out of place as special effects. Here, for example, is Operation Teapot – Turk, a March 7, 1955 blast that went off with the force of 43 kilotons.
LLNL says it's digitising the trove for historical purposes, but also because scientists can learn more about the tests by analysing the films more thoroughly than was previously possible. One problem the Lab's announcement explains is that mechanical cameras weren't perfect, so had variable frame rates. Digitising the films allows analysis of exact frame rates, which means it is possible to accurately calculate how fast and far fireballs travel and from that extrapolate the yield of each blast. As the different technologies used in each bomb are known, this enables new insights into the tests.
Weapon physicist Greg Spriggs says “We've … discovered new things about these detonations that have never been seen before. New correlations are now being used by the nuclear forensics community, for example."
And those correlations are available without the need for more tests, a welcome advance. ®
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