I was watching some slow motion footage of jet air planes breaking the sound barrier...I noticed that the wind enveloped over the wings and this "wind wake" continued to move toward the back of the jet until it folded in on itself and the "wind wake" caused a popping noise. I noticed what was really happening.
This is what was really happening:
The jet was pushing through the air so fast it caused the wind to clap. Just like a bullwhip does.
I studied a bullwhip action and found out it does not clap against itself...it pushes through the air so fast it causes the wind to clap. Like when one wave on the water crashes into another wave on the water...and we hear the "crash".
In fact, I bet I can take just about anything...like a towel...and make a loud popping noise by "popping it".
Cracking a bullwhip is not breaking the sound barrier...it's causing the wind to clap with a piece of leather pushed through the air fast enough.
In both situations, I mean both the jet air plane and the towell or bullwhip...the known variables are simple. We know they are solid objects moving through the air very fast, and they make a loud popping noise.
What we don't know is if this should be called breaking the sound barrier or not.
Maybe when you break the sound barrier there is no new sound at all. But when you break the wind barrier there is a loud popping noise.