To explain the moon's odd far side
a new hypothesis has been derived.
It's new 'neath the sun:
Two moons became one.
Wreaking havoc with early Earth's tides.
LA Times has the story of the new hypothesis. I was under the impression that calculations proved that the Moon was spun of the Earth after a collision of a Mars-sized planetoid. That explained the larger iron core of the Earth and the increased regolith and smaller core of the Moon.