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How dense would the atmosphere need to be to result in a cataclysmic chain reaction during a nuclear explosion? (lemm.ee)

submitted 5 months ago* (last edited 5 months ago) by [email protected] to c/askscience

11 comments fedilink hide all child comments

Famously, Oppenheimer and co worked out how close a nuclear bomb test would be to causing a chain reaction of nitrogen fusion in the atmosphere. They made a lot of worst-case-scenario assumptions and still came to the conclusion that no, a nuclear bomb test wouldn’t scour the surface of the world.

But let’s say the atmosphere was twice as dense as it is. Or ten times as dense. At what point would that calculation turn very, very scary?

Obligatory xkcd

Edit: man, seriously, most of the people ‘answering’ this question didn’t even read it.

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[–] [email protected] -2 points 5 months ago (1 children)

for fission, nothing in the atmosphere is fissable and so it can't. Fusion would be possible but that starts spontaniously via pressure.

at least that is how I read wikipedia, I await a real phyiscist to tell me how close I am.

[–] [email protected] 5 points 5 months ago

Yeah, you're not going to get a self-sustaining reaction in Earth's atmosphere if it wasn't already hot and compressed enough that there would be a self-sustaining reaction happening anyway. It's just not a plausible concern. You only get self-sustaining fusion in stars, so Earth would have to be a star in this scenario.