what causes a certain type of cloud to form around jets when they are accelerating past sound barrier?

Question

? thanks

Answer 1

Sound "waves" are actually compression patterns in the air. They can only move so fast, so when an object moves at the maximum speed of sound, these waves greatly overlap eachother to the point where they are visible to the human eye.

Answer 2

I believe what you are seeing (on occasion) is water condensing to form a cloud due to the change in density of the air across the shock.