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The white halo formed by condensed water droplets is thought to result from a drop in air pressure around the aircraft at transonic speeds

The sound barrier, in aerodynamics, is the point at which an aircraft moves from transonic to supersonic speed. The term, which occasionally has other meanings, came into use during World War II, when a number of aircraft started to encounter the effects of compressibility, a collection of several unrelated aerodynamic effects that "struck" their planes like an impediment to further acceleration. By the 1950s, new aircraft designs routinely "broke" the sound barrier


Some common whips such as the bullwhip or sparewhip are able to move faster than sound: the tip of the whip breaks the sound barrier and causes a sharp crack, literally a sonic boom. Firearms since the 19th century have generally had a supersonic muzzle velocity.