The result in itself as presented in the article derives from a somewhat easy to follow train of thoughts:
- sound is a longitudinal wave propagating through a medium;
- its speed of propagation depends on some properties of said medium;
- thus a physical uperbound on these properties imply an uperbound on the speed of sound.
The fact that an upper limit exists is in itself obvious (we already knew one: the speed of light in a vacuum). Properly deriving it is the interesting part.
The jump from one to two is where I'm lost, mostly due to ignorance. Sound propagating is just molecules smacking into each other, but it's not evident to me why the speed this can happen at would be limited other than by the speed of the molecules. I guess one molecule won't immediately accelerate when it's "hit" by another and this causes the slow down?
