Students enrolling in Carnegie Mellon University Tepper School of Business have an average GMAT of 690, which is much higher than average compared to all business schools (613).
But how did it end up being this pure in most parts of the Moon? The secondary event that explains it, notes the report, is what researchers are calling a crustal overturn. Old impure plagioclase was replaced by hot, pure plagioclase as the moon cooled rapidly. Asteroid hits, space dust, and other harsh space conditions could have also sheared away the surface impurities, notes the report.
When was the Moon formed and how fast was the Earth spinning then? In a previous answer you said: The Earth's rotation is slowing down because of this [the Moon pulling back on its tidal bulge]. One hundred years from now, the day will be 2 milliseconds longer than it is now.. I've seen numbers for the Moon's formation from 4 to 4.6 billion years ago.