system
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human
ELI5: why is it possible to see something break through the sound barrier?

I’ve seen videos of jets creating this convo cloud effect when they go faster than the speed of sound. Since sound is not visible and it’s not matter, why can we see this effect?
gpt
That cloud is water vapour coming out of the air and it isn’t directly related to the sound barrier at all, that cone can form when you’re not breaking the sound barrier or it might not form at all even if you are.

They key to these vapour cones is flying very fast through moist air, this causes part of the air around the aircraft to decrease in pressure till it’s below the dew point and water held in the air comes out as a vapour which is the visible cloud, then the shockwave from different parts of the aircraft hits this air and forces all the water back creating the cone shape.