A new analysis of dust from the Moon suggests that water may have come from the Sun.

It could be the result of bombardment of hydrogen ion from the solar wind, slamming into the lunar surface and interacting with mineral oxides. There could be significant quantities of water hidden in the lunar regolith.

Implications for our understanding of the provenance and distribution of water on the Moon are related to our understanding of the origins of water on Earth.

Recent studies have shown that there is more water up there than was thought. It is bound up in the lunar regolith and may be hidden as ice in permanently shadowed craters.

There are questions about how much water is up there. What is the distribution of it like? Where did it originate? The last question may have more than one answer.

It might have come from an asteroid impact. There are some from Earth. It's not the first thing that comes to mind when you think of rain clouds.

The wind of the sun is a reliable source of high-speed hydrogen ion. Evidence that includes an analysis of lunar dirt from the Apollo missions raises the possibility that the solar wind is responsible for some of the Moon's ingredients for water.

The chemistry in the grains recovered by the Chang'e-5 mission supports a solar source of lunar water.

They studied 17 grains. The low-latitude samples collected by Apollo and Luna were from a mid-latitude region of the Moon while the youngest known lunar volcanic basalt was collected from the driest basaltic basement.

The outer shell of the grain that is most exposed to space weather is the most altered in comparison to the grain interior.

The majority of the rims had very high hydrogen concentrations and low deuterium/hydrogen ratios. The ratios suggest that the solar wind deposited hydrogen on the lunar surface.

The Chang'e-5 landing site has a water content of 46 parts per million. That's consistent with some of the things that have been done.

The researchers conducted heating experiments on some of their grains to see if hydrogen could be preserved in lunar minerals. The grains can retain hydrogen after they're buried.

The simulations were done on the preservation of hydrogen in the lunar soil. The outgassing of hydrogen on the Moon is caused by the temperature of the lunar surface. A lot of solar wind-derived water could be retained at high latitudes.

The model suggests that the polar regions of the Moon could be richer in water due to the solar wind.

The Chang'e-5 samples have less water than the polar lunar soils.

This discovery is important for the future use of water on the moon. It is easy to use the water in the lunar soil through particle sorting and heating.

The research was published in a journal.