Wait wait wait! Theory about the "100 moons thing"! Because the Equestrian moon has the same gravitational effect on the tides as does the Earth moon, we can figure they must be identical or equal in their distance/mass ratio. However! The moon is very clearly much larger in the Equestrian sky, even without apparent distance (the moon appearing larger because other things seem smaller in the distance). Therefore, there are only two options. 1. The moon is larger, and the Earth smaller by comparison, or 2. The moon is much smaller, but closer to the Earth. The first option is plausible because the EQ moon shows no signs of parallax (spiralling around in the night sky over the course of a year), so we can assume that one side of Equestria always faces the moon, and one side of the Moon (the one with NMM's face) to always face the earth This is known as a double tidal lock, and causes for Hurricane Fluttershy to be plausible, because the oceans would always be in high tide in the area, and this it would be possible to swell it all up. However, when a moon enters double tidal lock with its parent, that's usually not good news, as they are both mutually pulling on each other's angular rotation, which is one of the main forces that keeps the earth spiralling around the sun. This means that in a few hundred thousand million years... EQUESTRIA'S END IS NEIGH!!! As for the second option, that is certainly possible, but that means that the moon would be much, much brighter than it is on earth (as it appears to be in the show), but also that moonlight would be slightly hazardous for your skin, as the sun is (the lack of atmosphere and the lustrousness of the lunar regolith allows very radioactive light to shine off of the moon). And thusly, Princess Luna would have come back looking like a bleached Half-life zombie! So, I repeat: EQUESTRIA'S END IS NEIGH!!! Oh yeah, these two theories would also affect the lengths of the month, so each reunion may be closer or further apart than 8 years. That's also kind of important.