Differences in space weathering between the near and far side of the Moon: evidence from Chang'e-6 samples.

The differences in terrain and chemical composition between the far side of the Moon (lunar farside) and the near side have been identified through remote sensing spectroscopy. The lunar farside samples returned by the Chang'e-6 mission show differences in terms of space weathering features compared to nearside samples. The studied farside samples lack vapor deposition layers found on the nearside and exhibit thinner amorphized layers, lower solar flare track densities, reduced number densities of nano phase metallic iron (npFe) and larger npFe grain sizes. These findings suggest that the solar wind plays a dominant role in space weathering on the Chang'e-6 sampling site, surpassing micrometeorite impacts. This could provide critical sample-based evidence of the lunar space environment's dichotomy, enhancing our understanding of how solar wind and micrometeoroid impacts shape the lunar surface, even over short exposure periods.