science

A fairly well accepted theory is that the moon's gravitational pull (tides) do a lot to churn earth's molten core, that churning adds heat and the mantle is a fantastic insulator. So all together, the moon is probably what's keeping our liquid core hot. (And in turn, the liquid core is probably what gives us our magnetic field. And the magnetic field is what keeps our atmosphere from blowing out into space. So that's all pretty important)

That tidal churn effect may also be why we have plate tectonics, which by the way is absolutely necessary to support life as we know it. Without plate tectonics, heavier elements would all sink to the center of the earth, but those churning plates are always bringing a mix of elements back up to the surface. And without some of those heavy elements, carbon based life wouldn't be possible. Also, technology wouldn't really be possible either, because if you think those rare earth metals are rare now, just imagine if they weren't found in earth's crust at all.

I think we have a lot to thank the moon for, it's probably the thing that does the most to make Earth a livable planet. Basically, if the Earth is special, the Moon is why.