Lunar Palaeoregolith Deposits as Recorders of the Galactic Environment of the Solar System and Implications for Astrobiology

TL;DR

Lunar palaeoregolith deposits hold a valuable record of the Solar System's galactic environment, which can inform our understanding of early Solar System history and astrobiology, making their exploration a key future goal.

Contribution

This paper highlights the importance of lunar palaeoregoliths as preserved records of galactic events impacting the Solar System, proposing their exploration for astrobiological insights.

Findings

Palaeoregoliths contain records of cosmic ray flux variations.

Galactic events like supernovae may be recorded in lunar deposits.

Locating these deposits is crucial for understanding Solar System history.

Abstract

One of the principal scientific reasons for wanting to resume in situ exploration of the lunar surface is to gain access to the record it contains of early Solar System history. Part of this record will pertain to the galactic environment of the Solar System, including variations in the cosmic ray flux, energetic galactic events (e.g, supernovae and/or gamma-ray bursts), and passages of the Solar System through dense interstellar clouds. Much of this record is of astrobiological interest as these processes may have affected the evolution of life on Earth, and perhaps other Solar System bodies. We argue that this galactic record, as for that of more local Solar System processes also of astrobiological interest, will be best preserved in ancient, buried regolith ('palaeoregolith') deposits in the lunar near sub-surface. Locating and sampling such deposits will be an important objective of future lunar exploration activities.