Breaking The Sound Barrier

Military aircraft routinely accelerate to speeds greater than the local sound speed. Historically, this was referred to as "breaking the sound barrier". The passage from subsonic to supersonic speeds is accompanied by some unusual phenomena which lie in the realm of "nonlinear" mechanical events - events involving some degree of chaos. One of the extraordinary sights associated with this supersonic transition is the production of a sudden visible vapor cloud around the aircraft. The report of the photographers is that they snap the shutter when they hear the sonic boom, which certainly associates the cloud with the breaking of the sound barrier. Here we have some beautiful images of airplanes breaking the sound barrier.