Well, I don't know physics, but from I heard of it, there are two kinds of phenomena that are sensitive to a rotation. One is quantum particles, they have fixed spin, but won't delve into that topic, because I suspect that their "spin" is like the charm of the charm quark, probably physicists just liked the sound of a word and used it. But there is one other thing I heard about: electromagnetism. If you run charged particles in circles, they create magnetic field that is directed perpendicularly to the circles, and the magnetic field feels different depending on the side of the circles being observed.

I see no way it influences the light emitted, but maybe I heard just too little of physics? BTW, does the direction of magnetic field of galaxies correlate with the direction of their rotation?

edit: Ah, maybe magnetic field can polarize the light? And when you have two magentic fields they polarize in one direction or in two different, and maybe it influences observed brightness of the light? Or maybe it is just an uninformed guess?