The punctuated evolution of the Venusian atmosphere from a transition in mantle convective style and volcanic outgassing.

A key question in the planetary sciences centers on the divergence between the sibling planets, Venus and Earth. Venus currently does not operate with plate tectonics, and its thick atmosphere has led to extreme greenhouse conditions. It is unknown if this state was set primordially or if Venus was once more Earth-like.

A South Pole-Aitken impact origin of the lunar compositional asymmetry.

The formation of the largest and most ancient lunar impact basin, South Pole-Aitken (SPA), was a defining event in the Moon's evolution. Using numerical simulations, we show that widespread mantle heating from the SPA impact can catalyze the formation of the long-lived nearside-farside lunar asymmetry in incompatible elements and surface volcanic deposits, which has remained unexplained since its discovery in the Apollo era. The impact-induced heat drives hemisphere-scale mantle convection, which would sequester Th- and Ti-rich lunar magma ocean cumulates in the nearside hemisphere within a few hundred million years if they remain immediately beneath the lunar crust at the time of the SPA impact.