The Equestrian Realm and The Functioning of Personal and Greater Magic

As an illustration, I would propose that the sisters do Not exert their influences on the courses of the Equestrian Sun and Moon directly but each are in-fact influencing these bodies indirectly via their influences on the dwarf singularity which, in turn, magnifies their influence in the capacity to which it physically represents a local universal disruption.  In this way, it can also be influenced to open other localized dimensional rifts and gateways under the influence of beings such as Discord.   (Discord it should be remembered spends his 'away' time in the realm of universal chaos in which such inter-dimensional disruptions are even more common so such warping capabilities would not be inconsistent with what he might be expected to perform in his native environment on a regular basis.)  Other extraordinary feats such as teleportations could be rationalized as representing lesser occurrences of the same types of dimension warping.