Not to be a buzzkill but I highly doubt that Unicron is the moon, being as the moon has too big effect on the earth with axis/rotation and with too many things on earth dependent on the moon, I'm sure Bay thought about that, or maybe not. Don't get me wrong Im all for Unicron being in this film but just dont think they would make him the moon. My guess is maybe the moon reference is that the decepts perhaps have secretly built a station below the moons surface since the last film waiting for their big moment. Thoughts?