why did scientists suspect that the moon cooled quickly?
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.