Icarus (in Press) Link to Article [https://doi.org/10.1016/j.icarus.2020.114199]
1Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH, USA
2Solar System Exploration Research Virtual Institute, NASA Ames Research Center, Moffett Field, CA, USA
Soil on the Moon is darkened by space weathering, a process generally assumed to be dominated by the solar wind and/or micrometeoroid impacts. Recent work, however, predicts that another process darkens the soil: large solar energetic particle events may cause dielectric breakdown (or “sparking”), melting, and vaporizing soil at a rate comparable to that of micrometeoroids. Unlike the solar wind and/or micrometeoroids, a combination of dielectric breakdown and micrometeoroid weathering can explain how the reflectance of the lunar maria varies with latitude at 750 and 1064 nm, and this combination provides a reasonable mechanism to explain how magnetic anomalies form prominent swirls in the maria. Consequently, space weathering in the lunar maria seems to be dominated by micrometeoroid impacts and dielectric breakdown.