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.
If the Earth's young atmosphere lost its water vapor, the surface would cool due to a decreased greenhouse effect. The young Sun was cooler and this contributed to a cooler surface. A small amount of CO2 in the atmosphere would enhance the greenhouse effect, warm the planet, and keep the surface mostly free of ice.