Deciphering the “Missing Xenon Paradox” in Celestial Bodies: A Multifaceted Perspective Toward Demystifying This Enigma

Abstract Xenon (Xe) is a heavy noble gas with intriguing chemical properties, such as having several stable isotopes and the ability to form compounds under extreme conditions. Despite the predictions based on cosmochemical models that suggest xenon should be relatively abundant in planetary reservoirs, empirical data indicate a significant depletion of this element in the atmospheres of Earth, Venus, and Mars. This discrepancy, widely recognized as the “missing xenon paradox,” has been the subject of extensive scientific inquiry. Many hypotheses have been proposed to resolve this anomaly, each addressing different aspects of xenon's behavior in planetary environments. This review summarizes recent theories and advancements aimed at resolving this enigma. Specifically, it discusses various proposed mechanisms, including atmospheric escape processes, interactions with the solar wind, geochemical sequestration within planetary interiors, and the potential role of biological systems in the xenon cycle. Additionally, it examines experimental and computational studies that provide insights into xenon's physicochemical behavior under diverse environmental conditions. By synthesizing findings across multiple disciplines, this review aims to offer a multifaceted perspective of factors contributing to the observed depletion of xenon in planetary atmospheres and interiors. It also highlights significant progress made in unraveling this complex issue while identifying key areas where further research is needed. Addressing these unresolved questions may ultimately advance the understanding of xenon's role in planetary evolution and contribute to broader insights into the geochemical and atmospheric histories of celestial bodies.