Eli5: Before the first atom bomb was detonated, there was some speculation that the chain reaction would keep continuing and lead to burning up the atmosphere. So what actually limits the size of the explosion?

Question

Eli5: Before the first atom bomb was detonated, there was some speculation that the chain reaction would keep continuing and lead to burning up the atmosphere. So what actually limits the size of the explosion?

In: Physics

Answer 1

That’s not really the thought.

The bomb would release energy at an energy density never seen before. The Air is 3/4 nitrogen and 1/5 oxygen. At some pressures you can burn nitrogen, producing nitrous oxides. This is one form of car pollution.

If nitrogen can burn and the air is 3/4 nitrogen, the question was “Would the bomb raise the energy high enough to set the whole atmosphere on fire?”. Calculations before the NM test indicated this was very unlikely, but “very unlikely” ≠ “it couldn’t happen”.

The nuclear explosion is limited by the amount of Uranium/Plutonium in the bomb.