Ask an Explainer

When an airplane or a jet flies, it changes the pressure of the air around it. Usually, this is slow and gradual, so these pressure waves will actually move the air out of the way of the plane, and the plane will fly smoothly through the air. However, start traveling at the speed of sound, and the airplane catches up to its own pressure waves. The air ahead of the aircraft is unable to move out of the way fast enough, and Boom! You start seeing shock waves. Shock waves are part of the reason that propeller planes cannot fly faster than the speed of sound.

Lightning also makes shock waves, that we hear as thunderclaps. We call this a sonic boom.