China's Chang'e-6 mission finds Earth's magnetosphere slows solar wind on Moon's near side

China's Chang'e‑6 lunar probe returned about two kilograms of regolith from the South‑Pole‑Aitken basin on the Moon's far side. Laboratory analysis by the Chinese Academy of Sciences showed that solar‑wind particles strike the far side at roughly 400 km/s, while on the near side the Earth's magnetosphere reduces their speed to about 200 km/s. The difference is recorded in the depth and composition of noble gases trapped in the lunar dust, preserving a billion‑year history of Earth's magnetic shield.

The findings, published in Nature Geoscience, provide the first direct comparison of solar‑wind effects on both hemispheres of the Moon and suggest that lunar soil can serve as a long‑term archive of changes in Earth's magnetosphere.