We are fairly confident about the idea that the Moon formed when a Mars sized object hit the young Earth over 4 Billion years ago.  The resulting debris cloud condensed to form the Moon, giving the Earth a surprisingly large Moon for its size.  Next to Charon and Pluto, the Earth’s Moon is the largest relative to the size of its planet.  It’s also the third largest of all moons in the Solar System, next to Ganymede and Titan, #1 and #2 respectively.  but there is one problem with this theory of the Moons formation: The Earth and Moon are...