Scientists have found the first evidence that particles from Earth can form water on the surface of its natural satellite.
Before the Apollo missions, everyone thought that the moon’s surface was dry like a desert because of the extreme temperatures and conditions of the space environment. Since then, various studies have shown the presence of water on our moon: ice in the shade of polar craters, water trapped in volcanic rocks or unexpected rusty iron deposits in the lunar soil. Despite these findings, there is still no real confirmation of the extent or origin of this water.
The dominant theory is that positively charged hydrogen ions are propelled by solar winds, bombard the surface of the Moon, and spontaneously react to create water in molecular form or as a hydroxide ion. However, a new international study, published in Astrophysical Journal Letters, submits the idea that solar winds are not the only source of ions that originate water. Researchers have shown that particles from Earth can plant the seeds of water formation on the moon’s surface. This would imply that other planets could contribute to the appearance of the element on their satellites.
Water in space
Water is widespread in space than astronomers initially thought. From the surface of Mars, to the moons of Jupiter passing through the rings of Saturn, comets, asteroids and Pluto, water has even been detected in clouds far beyond our solar system. It was previously assumed that water was incorporated into objects when the solar system was created, but it is increasingly evident that the functioning of space is much more dynamic.
Although the solar wind is an obvious source of water on the Moon, computer models predict that half of it should evaporate and disappear from high latitude regions during the three full moon days, when the moon is full. ci passes into the earth’s magnetosphere. Strangely, according to analyzes carried out by the Chandrayaan-1 satellite and its Moon Mineralogy Mapper (M3) tool, water does not disappear during this period. According to scientists, during the full moon period, when the Earth protects the satellite with its magnetic field, water should not regenerate as quickly as it disappears. The researchers found that this was not the case.
Solar Winds and Earth Winds
By comparing extensive mapping data of water on the Moon, during and before passage through the magnetosphere, the researchers came up with the idea that lunar water could be recharged by a wave of ions from the magnetosphere, called “Earth wind”. The Kaguya satellite confirmed the presence of these terrestrial ions near the Moon, while the Themis-Artemis satellite observed the characteristic profiles of ions from solar and terrestrial winds.
Kaguya’s observations during the full moon show a large concentration of oxygen isotopes from our ozone layer in the lunar soil as well as a large amount of hydrogen ions in our distant atmosphere called the exosphere. These particles are fundamentally different from those found in solar winds. The results of this study therefore go against the shield theory. They suggest that the magnetosphere itself helps supply the Moon with water.
A new avenue of research
In light of these findings, future studies of solar and planetary winds may tell us more about the evolution of water in our solar system and the potential effects of solar winds and magnetospheres on other moons and celestial bodies.
Carrying out this research will require new satellites equipped with spectrometers dedicated to the analysis of hydroxide ions and water. It will also require particle sensors orbiting the Moon, but also on its surface to fully confirm this theory. These tools will make it possible to predict which would be the best exploitable regions and the most suitable for the installation of a forward base.
The data could also be used to better prepare for future missions and better ensure the protection of humans and satellites against the dangers of particle radiation.
Source : phys.org