Why Are Sonic Booms So Loud?

If you've ever heard a sonic boom, you know that they're extremely loud. How do sonic booms form and why are they so ear piercing? We'll explain.

What Is A Sonic Boom?

A sonic boom is the sound made from an object traveling faster than the speed of sound, which is 761 MPH at sea level. The speed of sound actually changes with altitude and temperature, but we'll save that for another post.

Flight At High Subsonic Speeds

As an aircraft passes through the air at high subsonic speeds, it creates pressure waves around it. These waves are the same as sound waves, because sound is a change in pressure. Since pressure waves travel outward at the speed of sound, they continue to move further apart. While they may reach the ground, the pressure change caused by the waves is so small it is unnoticeable.

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Flight At Supersonic Speeds

When an airplane accelerates above the speed of sound, it starts moving faster than the pressure waves. The waves begin to pile up on each other and magnify in intensity. The many small pressure waves merge into a single shock wave moving at the speed of sound.

The shock wave creates a rapid, intense expansion and contraction of air which reaches the ground. When the shock wave passes over you, it unleashes a loud clap of noise. That's why sonic booms are so loud.