Water Could Form on the Surface of the Moon, Thanks to the Solar Wind

The surface of the Moon could act as a chemical factory, creating water from rocks, according to a new computer model from NASA. Researchers found that the solar wind — a stream of charged particles coming from the Sun, could form water when it strikes the surface of our planetary companion.

The solar wind strikes the surface of the Moon at speeds around 450 kilometers per second (almost one million miles per hour). When that happens, the stream can enrich the rock, forming water.

“We think of water as this special, magical compound. But here’s what’s amazing: every rock has the potential to make water, especially after being irradiated by the solar wind,” said William M. Farrell, a plasma physicist at NASA’s Goddard Space Flight Center, one of the researchers who helped develop the simulation.

The Moon was once thought to be dry and barren. But, the more we look, the more water we see. Image credit: Nigel Howe/Flickr

The simulation shows that when positively-charged protons in the solar wind strike the surface of the Moon, they can interact with the negatively-charged electrons surrounding the molecules of lunar crust, releasing hydrogen (H) atoms. These can join with oxygen (O) contained within silica in the surface, forming hydroxyl (OH), which may later join with other hydrogen atoms, creating water (H2O).

This is the process by which solar wind, interacting with the lunar surface, might produce water. Image credit: NASA/JoAnna Wendel

Evidence of water at the poles of the Moon has been detected by spacecraft, but researchers theorized the material may have arrived there from icy comets crashing on the surface. Once protected within the shadows within craters, the ice would remain perpetually frozen. However, this new research suggests a different process may be in play on the surface of the Moon.

This new simulation also suggests why varying levels of hydrogen are found when looking at different areas of the Moon. Around the equator, where it is warmer, sunlight energizes hydrogen atoms, driving them off the surface, where they escape to space. Near the poles, the amount of heating is greatly reduced, leaving a greater amount of hydrogen on the surface.

The solar wind affects bodies around the Solar System in different ways. Here is a look at some of its effects. Image credit: NASA’s Goddard Space Flight Center/Mary Pat Hrybyk-Keith

Water is one of the most precious resources humans will need as we journey across the Solar System, populating other worlds. If this study is correct, this life-giving substance could be more common on the Moon than we previously believed.

“Water in its various forms pervades the solar system, from traces of water vapor on the Sun itself to water ice in the likely composition of Pluto and the Kuiper Belt objects beyond it. Even without its link to the question of extraterrestrial life, water would be an important theme in exploration of the solar system, as a possible resource and as a substance that’s geologically intriguing in its own right. Water ice on the Moon and Mars might help supply future human explorers,” Jet Propulsion Laboratory reports.

This process is likely not contained to the Moon, but would also take place on every silica-rich surface in the Solar System, from asteroids to grains of sand. This could make water far more common in our planetary neighborhood than once believed. If so, populating the planets and moons of our Solar System just became a whole lot easier.