Lunar soil record of atmosphere loss over eons.

Nie, Nicole X; Dauphas, Nicolas; Zhang, Zhe J; Hopp, Timo; Sarantos, Menelaos · Sci Adv · 2024

basic_science · Level V

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Abstract

The Moon has a tenuous atmosphere produced by space weathering. The short-lived nature of the atoms surrounding the Moon necessitates continuous replenishment from lunar regolith through mechanisms such as micrometeorite impacts, ion sputtering, and photon-stimulated desorption. Despite advances, previous remote sensing and space mission data have not conclusively disentangled the contributions of these processes. Using high-precision potassium (K) and rubidium (Rb) isotopic analyses of lunar soils from the Apollo missions, our study sheds light on the lunar surface-atmosphere evolution over billions of years. The observed correlation between K and Rb isotopic ratios (δ <sup>87</sup>Rb = 0.17 δ <sup>41</sup>K) indicates that, over long timescales, micrometeorite impact vaporization is the primary source of atoms in the lunar atmosphere.