Sonic boom is a loud noise caused by an object–usually an airplane–flying at a supersonic speed. To a person on the ground, it may sound like a clap of thunder. The noise results from a shock wave produced by the plane. A shock wave is a pressure disturbance that builds up around a plane flying at a supersonic speed. It results from a change in the air-flow pattern around the plane’s leading edges. Sonic booms cannot hurt people, but they may damage plaster walls and break windows.
A plane reaching the speed of sound is said to be crossing the sound, or sonic, barrier. Captain Chuck Yeager of the U.S. Air Force became the first person to break the barrier. He did so in a Bell X-1 rocket plane on Oct. 14, 1947.
