NASA confirms the presence of water in the moon's sunny regions
Water on the lunar surface cannot only be found in cold, shady craters near the poles. At a recent NASA conference, scientists confirmed that water is more abundant on the Silver Globe than previously thought and can even be found on the sunlit surface of our natural satellite.
Until the end of the last decade, scientists thought the moon was a rather dry place. Everything changed when India's Chandrayaan probe discovered water in the form of water ice in constantly shaded craters near the poles in 2009. Since then, numerous studies have shown the presence of water ice in places with consistently low temperatures. Now, in two new studies, the scientists have not only confirmed the presence of water on the moon, but also discovered that there could be many "cold traps" on the surface of the Silver Globe that contain water, including in areas that sunlight gets in.
Water on the moon
The Stratospheric Observatory for Infrared Astronomy (SOFIA) confirmed the presence of water on the sunlit surface of the moon for the first time. The research instruments discovered water molecules in the Clavius crater in the southern hemisphere of the moon, one of the largest craters visible from Earth.
Previous observations of the lunar surface detected some form of hydrogen but were unable to distinguish water from its close relative, the hydroxyl (OH) group. The measurements left a shadow of uncertainty. Something absorbed infrared waves 3 micrometers long, but the scientists weren't entirely sure if it was really water because this hydroxyl group also has the same absorption spectrum.
Doubts were dispelled by two new studies published in Nature Astronomy by Paul Hayne, who works for NASA and the University of Colorado, Boulder and Casey Honniball, of NASA's Goddard Space Flight Center.
The data obtained from the Clavius crater indicate the presence of water in concentrations of 100 to 412 parts per million trapped in the cubic meter of lunar soil - the regolith. For comparison: it is 100 times less than in the Sahara. Despite the relatively small amounts, this is an important discovery.
Water is a precious resource in space and a key component of life, at least as we know it. NASA wants to know all about the presence of water on the moon before sending people there as part of the Artemis program, slated for 2024. It is planned to establish a permanent human presence on the moon by the end of the decade. The presence of water can make this a lot easier. However, the zeal can be cooled by the fact that the discovered water will not be easily accessible and that it will only have to be obtained with great effort.
Where does the water on the moon come from?
- Without a dense atmosphere, the water on the sunlit surface of the moon should just disappear into space, "said Honniball. - But somehow we saw it. Something is producing water and something has to hold it there," she added.
Several forces can be involved in the supply or production of this water. One of the concepts is that it rains micrometeorites that fall on the surface of the moon and carry small amounts of water with them. Another possibility is a two-step process in which a solar wind from the sun delivers hydrogen to the surface of the moon, which forms hydroxyl groups in chemical reactions with minerals in the oxygen-containing regolith. The radiation generated when bombarding micrometeorites can convert hydroxyl groups into water. Water has also been found on the moon since the beginning of its existence. It could not be fed by the rain of tiny meteorites, but by a larger comet. How water is stored without escaping into space also raises fascinating questions. Scientists suspect that water can be trapped in the soil in tiny spherical structures that were created by the impact of micrometeorites, ie glass material made from rhegolite. Another possibility is that water can be hidden between the grains of the lunar soil and shielded from the sun, possibly making it a little more accessible than glassy, microscopic spheres.
How much water is that
There is a second article about water on the moon in the same issue of Nature Astronomy. A team led by Hayne used data from the Lunar Reconnaissance Orbiter to create models of the distribution of water on the lunar surface. Scientists showed that water can be trapped in tiny, shady places called "cold traps", where the temperature stays below zero. According to the researchers, such traps could be located on a larger area of the moon than expected.
Haynes team found that "cold traps" can cover an area of up to 40.000 square kilometers. These traps can vary in size, from traps less than an inch in diameter to really tiny traps hundreds of times smaller. According to the scientists, most of these areas are located near the poles.