Ah, true, you can have an object exceeding the speed of light in some medium, and that does result in an effect analogous to a boat wake or a sonic boom, from “photons piling up on each other”.
I like the ones that ask, “If this thing violated the laws of physics, what do the laws of physics say would happen?”
That’s what I was trying to answer with my post about turning into pumpkins. There’s just no good answer, so magical things happen. Or not. And I don’t think @Kedikat was thinking of Cherenkov radiation.
I wasn’t. I was wondering if such an effect would happen, that is why it can’t happen. Why an object can’t travel faster than light.
I’m not sure how meaningful it is to point to one of the specific counterfactual results of a counterfactual situation, and say that that’s the specific reason it doesn’t happen. There are lots of other unphysical things that come up if you try to follow that chain of reasoning, and any of them can be pointed at as “the reason”.
The stuff that goes at the speed of light is massless particles. Photons have momentum, but zero mass. Nothing can go faster than the speed of light because that is geometrically impossible (to understand this you have to let go of the Newtonian view of the universe; it does not work like that).