Arpita Roy proposed, with collaborators, a physical explanation for the lunar crustal dichotomy: the Moon's farside crust is thicker on average than its nearside crust. Their primordial Earthshine hypothesis connects this asymmetry to unequal irradiation by a hot post-impact Earth.
If the young Moon was already in synchronous rotation, the permanently Earth-facing side would have received more radiation. The proposed temperature gradient would favor condensation of crust-forming refractory material on the cooler farside. The explanation is a model of how a thermal asymmetry could seed a compositional one; it depends on the early locking, cooling and mixing history.[ref]
Earthshine on a Young Moon: Explaining the Lunar Farside Highlands by Arpita Roy and others. Abstract and sections 2–4: early locking, irradiation gradient, condensation and mixing requirements
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