)
Hell, even if Equestria's universe is geocentric, then that means the _*sun_* has to spin around the planet because of the gravity pull.
I guess you could make the argument that Celestia and Luna accelerate the speed the sun and moon rotate around the planet to compensate for that, and it's like a wind-up box in that they need to keep "pushing" them, but that would mean the moon is also tidally locked to the planet's rotation, and I'm pretty sure that would mean there's something **very** wrong with the planet at that point.