Boom, Here comes the Boom.

Actually, there is not just a single boom; as long as an aircraft is moving faster than sound through the atmosphere, a sonic boom can be heard each time the surface of a cone-shaped shockwave intersects with a set of eardrums.

Many authorities suggest that what happens in three dimensions in the air can most easily be visualized by watching the waves produced in front of a boat in the water, with the boat moving through them. If the boat is traveling at a great speed, the water cannot get out of the way of the bow, and the compression of the waves in front of it increases, producing great turbulence that collects as a V-shaped wave spreading in the wake of the boat.

For an airplane, the waves are sound waves, alternating areas of compression and rarefaction of the air. The waves are pushed closer and closer together as the plane flies faster and faster, again creating great turbulence and buffeting.

If the plane reaches speeds faster than the speed of sound, the turbulent waves collect in a cone-shaped wake, with a boom audible along its surface. The sound owes its explosive quality to the sudden, rapid changes in air pressure along the surface of the cone.