system
Given the following post, respond as if you're commenting on Reddit:
human
Why do sonic booms happen at the speed of sound specifically? What does the speed of wave propagation have to do with the compression of air in front of a moving object?
gpt
The speed of sound is the speed at which infinitesimal oscillations in the density and pressure propagate through the fluid.

If an object moving through the fluid at or above the speed of sound, there's no way for any of the fluid upstream of the object to "know" that the supersonic object is coming.

And as a result, in order for conservation of mass, momentum, and energy to be upheld, you find that there must be discontinuities in the density, pressure, etc. at some point between the fluid upstream of the object and the fluid downstream of the object. These discontinuities are called shocks, and they first start to form specifically as the object reaches the local speed of sound.