Did the non-zero risk of the atmosphere igniting increase as nuclear weapon yields got larger and larger?
Obviously a result of watching Oppenheimer.
In: 789
Also remember that quantum things are very often probability based you can never rule something out mathematically.
*Oppenheimer* exaggerates the severity of the concern, here, in service of the dramatic irony of Robert Oppenheimer believing he’s “ignited” nuclear conflict between world powers. Manhattan Project scientists actually *didn’t* think the atomic bomb (or Teller’s later thermonuclear bomb) would ignite the atmosphere, but the question having been raised, they sought mathematical proof that it was impossible. That’s been altered in the storytelling for the situation to be that they thought it *might* and tried to prove that it *could*, but it’s really the opposite of that.
What do we want to know here?
If the bomb explodes it creates a plasma ball creating a similar environment to the Sun. So how much air-plasma we need at what temperature for air fusion to be a self-sustaining process.
There are two factors: The amount of energy the pasma ball loses to the environment and the amount of energy the air fusion adds to the plasma ball.
Questions: What temperature does the plasma need to reach for air fusion to happen? Can we achieve that? What size is required from the plasma ball at around that temperature?
(Cause the larger the plasma ball the more air it come in contact with so can fuse more air per unit time. There must be a tipping point. But is its a sphere of 1km in radius or half the atmosphere?)
So lets calculate something nobody ever calculated before. We need upper limits on the energy released from the explosion. Which tells us the max size and temperature of the plasma ball and we need lower limits on dissipation. That gives us a worst case scenario and lets calculate where the ignition point is. As calculations got more detailed more mechanisms for dissipation were uncovered increasing the energy requirements for the ignition point.
But still this isn’t a theoretical impossibility but a technical one. And a really big technical one. And why emphasise that it’s non-zero probability. Well QM and nuclear physics was quite new. So what if we are wrong about the behaviour of matter at high energies? Later on with the first fusion bomb the scientists thought that a filler material was inert (not driving the reaction) but at high enough energies it was about as effective as the fuel Lithium6 and Deuterium in the form of Lithium Deuteride. So the bomb ended up exploding with not 4-5 MT but 15. We know this as the Castle Bravo incident.
With the data available for the calculations, the risk was 0%.
However, there was a chance the data used was not 100% correct and if certain values woud deviate more than x% from what was assumed, the potential results would be concerning.
The percentage is about the deviation required, not about the risk calculated.
The media explained it wrong and the exciting headlines remained in the peoples memory.
Kyle Hill made a good video about this. It may not be totally ELI5 but it should answer your question better than the comments here. Not to say that the comments are wrong, but the video gives a good explanation.
If you watched Oppenheimer, I’m sure you can manage this video.
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