 Primordial Earthshine hypothesis

A proposed explanation of the lunar farside highlands in which irradiation from a nearby hot early Earth imposes a thermal gradient on a synchronously rotating, accreting Moon. Preferential condensation and deposition of refractory crust-forming material toward the cooler farside seeds a lasting chemical and crustal-thickness asymmetry. It requires early synchronous rotation, appropriate transport times and incomplete homogenization by subsequent mixing. It is a testable formation hypothesis, distinct from ordinary present-day illumination of the lunar night side.^[ref]