It was intuitive, it was said, it was suggested, but now there is a certainty: there is water on the moon.
The confirmation came from an article by various scientists, published in Proceedings of the National Academy of Sciences, with the collaboration of NASA researchers.
The water is located in the darkest and coldest parts of the polar regions. It is in unevenly distributed ice deposits, which may be old.
According to the study, the largest part of the ice is concentrated in the craters in the south pole, while in the north the liquid is distributed in larger quantities but in a very widespread way.
That there is more in the craters in the south is that it has more cold spots.
Already in the 60s there was the possibility of water in the dark places of this natural satellite of the earth, as well as in other parts of the solar system such as Mercury and the smaller planet Ceres.
More recent are the findings of the Lunar Reconnaissance Orbiter probe from NASA and Chandrayaan-1 from India, which reported the presence of hydrogen in the vicinity of the moon sticks.
But that, in the words of Shuai Li, from the University of Hawaii, lead author of the study, might be because of the existence of hydroxyl or something else with hydrogen, not just water.
That hydrogen can also come from the solar wind, those high-energy particles that constantly hit the moon.
And the possible existence at the South Pole, suggested by another observation, could have been related to another phenomenon, such as an unusually reflective soil, NASA explained.
On this occasion, Li, together Richard Elphic, from the NASA Ames Center and a few other colleagues, studied the Moon Mineralogy Mapping Instrument (M3) data to identify three specific signals demonstrating the existence of ice on the lunar surface.
That instrument, on board the Chandrayaan-1, was designed to confirm the presence of solid ice. He also collected data on the reflective properties that are characteristic of ice and immediately measures how molecules absorb infrared light, which can distinguish between liquid water, steam or ice.
The identified water is a few millimeters below the surface, the researchers wrote in the article.
Because the moon has a small slope on its axis, relative to the plane on which the sun rotates (ecliptic), it causes depressions in the polar areas, such as craters due to collisions of objects, and ensures that they are always in the penumbra. stay.
They are places where the highest temperature reaches -156 ° Celsius, while the lowest temperature reaches -238 °.
The water in this star is stored differently from that of Mercury and Ceres, where it forms a continuous spot.
So a body that was considered dry and hostile could eventually be more beneficial because human expeditions could get water from those deposits.
Because the lunar orbit stabilized only 2,000 to 3,000 million years ago, this suggests that the water arrived through comets that hit the surface and more recently by meteorites, a fact that would explain the disposition in patches.