Solar wind implantation is thought to be one of the primary mechanisms in the formation of water (OH/H2O) on the surface of the Moon and possibly on the surface of other airless bodies. The lunar nearside spends ~27% of its daytime in Earth’s magnetotail where the solar wind flux is reduced by as much as ~99%. However, no correlated decrease in surficial water content has yet been seen on the lunar nearside. Here we report abundance observations of lunar surficial water on the nearside at different stages during the Moon’s passage through Earth’s magnetotail. We find that the water abundance at lunar mid-latitudes substantially increases in the dusk and dawn magnetosheath when the solar wind flux increases, yet remains nearly constant across the central magnetotail. We suggest that although we have confirmed the importance of the solar wind as a major source of fast water production on the Moon, hitherto unobserved properties of the plasma sheet properties may also pl
Granites are nearly absent in the Solar System outside of Earth. Achieving granitic compositions in magmatic systems requires multi-stage melting and fractionation, which also increases the concentration of radiogenic elements1. Abundant water and plate tectonics facilitate these processes on Earth, aiding in remelting. Although these drivers are absent on the Moon, small granite samples have been found, but details of their origin and the scale of systems they represent are unknown2. Here we report microwave-wavelength measurements of an anomalously hot geothermal source that is best explained by the presence of an approximately 50-kilometre-diameter granitic system below the thorium-rich farside feature known as Compton–Belkovich. Passive microwave radiometry is sensitive to the integrated thermal gradient to several wavelengths depth. The 3–37-gigahertz antenna temperatures of the Chang’e-1 and Chang’e-2 microwave instruments allow us to measure a peak heat f