“Most films of nuclear explosions are dubbed. If they do contain an actual audio recording of the test blast itself (something I’m often suspicious of — I suspect many were filmed silently and have a stock blast sound effect), it’s almost always shifted in time so that the explosion and the sound of the blast wave are simultaneous.
This is, of course, quite false: the speed of light is much faster than the speed of sound, and the cameras are kept a very healthy distance from the test itself, so in reality the blast wave comes half a minute or so after the explosion. Basic physics that even a non-technical guy like me can understand.
It’s rare to find footage where the sound has not been monkeyed with in post-processing. So I was pleased when a Russian correspondent sent me a link to footage digitized by the National Archives of a 1953 nuclear test. The footage is very raw: it hasn’t been edited much, and is a bit washed out, but the audio is still in “correct,” original sync.
Click the image to go to a YouTube edit of the video that I made. You can see the original via NARA’s page….
The video starts off pretty dark and muddled, but don’t let that turn you off. What’s interesting about this clip is not the visual aspects. The test looks like any old nuclear test, but with poor film quality.
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.” (Restricted Data: The Nuclear Secrecy Blog)