The video of the "Tsar Bomb" has very clear components of the initial visuals of the blast. :eek: 
I know about the mushroom cloud–that it exists, only, not why–but it has such a clear double-donut…what’s that? As well as the stuff billowing up from the ground, and I guess a shock wave emanating through the atmosphere?
Thanks,
Leo
Here’s one trusted source on the topic.
Um, just so you know, that’s not a real video. It’s just an animation.
First, a mushroom cloud is a feature of most any ground explosion, its not unique to nuclear ones and is not caused by there, um, ‘nuclear-ness’. It just makes the mushroom cloud enormous.
The three main components of a nuclear blast are:
[ol]
[li]Heat (again, common to any explosion)[/li][li]Blast or over pressure (also common)[/li][li]Radiation (unique to nuclear explosions)[/li][/ol]
The ‘doughnut holes’ you see are atmospheric disturbances caused by the intensely fast & strong shockwave. Again, any explosion can cause these but the extreme power and size of a nuclear blast also makes them extremely large and visible.
You’re right, but it was pretty well done. I think this clip is the real deal.
More specifically:
these are condensation of atmospheric humidity caused by a temperature drop associated with the rarefaction wave immediately following the compressive shock wave. Instead of being a contiguous spherical surface, we see rings because of the different conditions at different altitudes in the atmosphere: at some levels the initial temperature and humidity are such that the blast wave does not cause condensation.
Like the mushroom cloud, these condensation rings are not unique to nuclear explosions; they can happen in any explosion that produces a shock wave. A condensation front is visible emanating upwards during the first explosion at Fukushima (here, at 0:24); note that this was a hydrogen chemical explosion, not a nuclear explosion. It’s also visible in this photo from Operation Sailor Hat, which was a half-kiloton conventional explosive test. Finally, I’ve also seen them during footage of aerial bombing of the jungle during the Vietnam war; these are ideal conditions for forming these condensation waves, i.e. very high relative humidity. Note that in the case of the 4.2 kiloton Minor Scale conventional-explosive test, which took place in the low-humidity environ of New Mexico, no condensation front is visible.
If that’s Tsar Bomba, it’s not very vivid footage, just because there isn’t much else you can see for context. I’m rather more impressed by the Castle Bravo test, if only because you see so much more of the effects. Like the clouds melting. And the heat baking water from the trees miles away. And the shockwave.
Edited to add: if you want to hear what an atomic bomb really sounds like, this video has the actual sound of the blast: Operation Upshot-Knothole, shot Annie. It’s pretty much a loud “pow!” Because of the distance from the detonation, it takes about 30 seconds to heard the blast after seeing the explosion.
More on why mushroom clouds exist.
