sonic booms

[postino]

What causes a sonic boom when a plane breaks the sound barrier

[Rev. Green]

Normally, all the sound from a plane reaches you at different times - you hear it it one part of the sky, then in another part. But when a plane travels at the speed of sound all the sound reaches you at the same time.

[vrach]

A plane traveling faster than the speed of sound(330 m per sec) will always be able to "run away" from its own sound(noise).As the plane drops speed,e,g.approaching an airport,"old" noise,closely trailing it will collide with "new' noise producing a CLAP (sonic boom)-unfortunately, usually near residential areas close to airports!