The Moon is a weird satellite as it is way too large by comparison to the moons of other planets we know of. It also sits at a near perfect distance to completely block out the sun whenever it is in alignment with it. And the fact it is ringing like a bell when a heavy object strikes it makes some people believe the moon is hollow, and was created instead of naturally formed.
Who did it? I am not sure we will ever know, but I am open to the possibility that it indeed was placed here to keep the Earth stable. Heck, we might even have done this ourselves , once we evolved enough on the unstabiblized world . Invent time travel and then make it back to the past to make our little blue marble safer for those living on it.
