how did the moon come to be? orpheus, a planet the size of mars, collides into earth. the collision meshed the two planets together and the fragments become moon. that is why no rock on moon actually defers from that on earth. how would earth be without the moon? the moon stabilizes the earths tilt which regulates its temperature against the sun. without the moon the earths tilt will become anywhere between 0-90 degrees vs less than 1 degree now. so stable vs wobble. simply put, without it the sahara would turn into north pole and back, on a regular basis. and the north pole into Sahara and back, erasing any life that can not exists in both extreme weathers. without the collision, and the moons creation, man would not have existed. now…. fact: the moon recedes from the earth 1.5″ a year. at some point the moon will loose its orbit around earth and part. so the end may not be today but it is actually inevitable. also here’s a good basic documentary on the subject. by xy