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.
Other factors affecting rotational speed include the rapidity of a planet's initial formation (faster collapse means more angular momentum conserved) and impacts from meteorites, which can slow down a planet or knock it off stride. Earth's rotation, he adds, is also affected by the tidal pull of the Moon. Because of the Moon, the spin of the Earth is slowing down at a rate of about 1 millisecond per year. The Earth spun around at a faster clip in the past, enough so that during the time of the dinosaurs a day was about 22 hours long. In addition to slowing the Earth's rotation, the Moon's tidal pull is causing the Moon to slowly recede from the Earth, at a rate of about 1 millimeter per year.