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.
The initiation of a snowball Earth event would involve some initial cooling mechanism, which would result in an increase in the Earth's coverage of snow and ice. The increase in Earth's coverage of snow and ice would in turn increase the Earth's albedo, which would result in positive feedback for cooling. First breath: Earth's billion-year struggle for oxygen New Scientist, #2746, 5 February 2010 by Nick Lane. 2  Posits an earlier much longer snowball period, c2.4 - c2.0 Gya, triggered by the Great Oxygenation Event.