Our moon is critical to advanced life.. but why is it there?

I think that the origin of the moon is a really interesting topic. The usually favored hypothesis of a collision with a Mars-sized planet fits many observations, but would seem to be a really rare and potentially fine-tuned event, given that the moon is so vital to advanced life on earth. This paper suggests that either the collision hypothesis is really wrong or our models are wrong. I would guess our models are wrong. In either case, it doesn’t make the formation of the moon seem any simpler to explain.  Clink on the line below.