Re: Fascinating stuff
"It does beg the question of whether it might even be possible for the speed of sound to be faster than the speed of light.
In order for a pressure wave to pass through a medium, the particles have to react to each other. That reaction---the force that causes them to move---is typically communicated through light (photons) so particles can't react to each other faster than photons can shuffle between them.
Light isn't the only option. But all massless bosons (e.g. gluons) are limited to the speed of light. And massive particles always travel slower than massless ones. So particles can't react faster to each other than light can move between them. And if they can't react faster than light, then a sound wave can't propagate faster than light.
There are probably issues close to the Planck scale. But I'm not sure they apply here.