A sound source moving faster than sound produces what loud phenomenon?

A sound source moving faster than sound produces a sonic boom.

As an object travels through air, it creates pressure waves that move outward at the speed of sound. At subsonic speeds, those waves can spread ahead of the object. Once the object becomes supersonic—faster than Mach 1—the waves pile up and merge into a shock wave. An observer who is hit by that sudden pressure change hears a sonic boom.

The boom is not simply a one-time noise made at the instant an aircraft crosses the sound barrier. A supersonic aircraft continuously generates a shock-wave pattern while it remains above the speed of sound. This pattern forms a Mach cone, and people hear the boom when that cone sweeps over them. Aircraft design, altitude, speed, weather, and atmospheric conditions affect its loudness.

A sonic boom can sound like an explosion or a sharp thunderclap. The crack of a supersonic bullet and the snap of a bullwhip are smaller examples of the same basic phenomenon. “Resonance,” “beat,” and “echo” describe different ideas: resonance is amplified vibration, a beat is interference between nearby frequencies, and an echo is a reflected sound.