It was spinning rapidly, pushing the heavier elements to the surface...then what happened, did the batteries run out? Take a look, it's not spinning at all! Pretty weird considering its violent birth.
Frank, try this:
In the earliest solar accretion event the heaviest elements accreted first out of the gas/dust cloud creating heavy cores in the planets
In the secondary event – the Earth/lesser body collision - the heavy central core of the lesser body sank and became a part of Earth's core, the lighter material mixed with the surface of the Earth and flew on into Earth orbit as a cloud of lighter material accreting in orbit around the Earth.
As I see it, and correct me if I'm wrong, the only problem we have is that it is believed that the heaviest elements are at the surface rather than in the core of the moon. The collision event is very early in the Earth/Moon formation process. There was plenty of time for heavy elements to have collided and accumulated on and becoming a part of Luna's outer surface, and stabilized there.
Therefore, the debris blown out of both Earth and the impactor came from their iron-depleted, rocky mantles. The iron core of the impactor melted on impact and merged with the iron core of Earth (From the models which develop from mathematical formulae – the same formulae that give us all other explanations for time and space)
I find developing possible scientific explanations far more fascinating and satisfying than taking short-cuts involving processes we have never seen before.
Some things we know:
FACT - Earth has a mean density of 5.5 grams/cubic centimeter, but the moon has a density of only 3.3 g/cc. The reason is the same, that the moon lacks iron.
FACT - The moon has exactly the same oxygen isotope composition as the Earth, whereas Mars rocks and meteorites from other parts of the solar system have different oxygen isotope compositions. This shows that the moon formed form material formed in Earth's neighborhood.
FACT – The moon year and day are the same – it is tidally locked – This situation prevails with all Jupiter’s and Saturn’s nearer satellites. In the Earth/Luna collision theory the moon accreted in orbit about 14,000 miles from Earth, and has been moving away ever since. At that distance it would’ve become tidally locked quickly.
BTW Frank, I am not flaming you; I hope I am engaging you