Eli5 what is the force behind a sonic boom?

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I know it comes from breaking the sound barrier, but why a boom instead of complete silence?
I have the understanding it creates a physical wave too.
Bonus questions: Does the pilot hear it?

Can the same thing be achieved underwater?

Related: I know the speed of sound is faster under water, does any reaction happen theoretically at the air speed of sound underwater?

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13 Answers

Anonymous 0 Comments

Have you ever had a stereo turned up so loud you could feel it in your ear Le and your torso? That’s the wave pressure of the sound.

When a craft moves faster, that wave is being dragged along the skin of the craft, so that it builds up into a BIG wave before (continually) falling off the back; making a constant roar. From the ground, it’s a boom as it passes because the plane is moving.

The pilot doesn’t hear the boom; he’s moving faster than it and always ahead of it. Much like a ship in orbit doesn’t hit the ground because it’s moving so fast that it misses.

It _could_ be done underwater! However, water is very very dense; and it takes much more energy to accelerate through water. There is a theory that may have engineering application such that a torpedo is covered with tiny holes, and continually pushes out high-pressure steam to reduce its drag, and therefore move faster than sound in water.

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