Monday , November 29 2021

Water in the Craters of the Polar Moon Not as invincible as expected


Inside Dark, Polar Moon Crows

Permanently shaded moon crater. Credit: NASA Space Flight Center

The moon's South Pole region is home to some of the most extreme environments in the solar system: it is an unimaginably cold, massive crater and has areas that are either constantly bathed in sunlight or in darkness. That is why NASA wants to send astronauts there in 2024 as part of its Artemis program.

As a result of constant darkness, NASA's Moon Reconnaissance Orbiter (LRO) has measured the coldest temperatures in the solar system within those craters that have become known as the perfect storage medium for water, for eons. Or so we thought.

It turns out that despite the temperature, which is down to -388 degrees Fahrenheit (-233 degrees Celsius) and is likely to keep frost in the soil almost forever, the water slowly emerges from the topmost, super-thin layer (thinner than the width of the red blood cell) on the surface of the Moon. NASA scientists reported this recently in an article in Geophysical Research Letters.

Crows of the polar moon

This animation shows evidence of high concentrations of hydrogen at the South Pole of the Moon. In 1998, NASA's Lunar Prospectus mission identifies hydrogen on the Moon, an early evidence of potential ice depositions. As you can see in this video, Prospector data showed significantly more hydrogen (shown in blue) at the South Pole of the Moon.
Credits: NASA Godadd Spacecraft Science Visual Exploration Studio

"People think of some areas in these polar craters as water retention and that's all," says William Farrell, a NASA plasma physicist, Greenbelt Center for Space Flight, Maryland, who led the study of moon cold. "But there are particles of the solar wind and meteorites that hit the surface and can cause reactions that usually occur at warmer temperatures on the surface. This is not underlined.

Water Not as invincible as expected, scientists say

A high-resolution, high-resolution gravity map based on data returned by NASA's weight-recovery mission and the indoor laboratory covered by the ground based on NASA's LNB and camera data. The view is south, with a south pole near the horizon in the upper left corner. The Terminal runs through the eastern edge of Schrödinger's pool. Gravity is painted on areas that are in or near the night side. Red corresponds to mass exceses and blue to mass deficiencies. Credits: NASA Scientific Visualization Studio

Unlike the Earth, with its plush atmosphere, the Moon has no atmosphere to protect its surface. So when the Sun is spraying charged particles known as the Solar Wind in the Solar System, some of them bombard the surface of the moon and raise water molecules that jump around new places.

Likewise, the gloomy meteorites are constantly crashing to the surface and eradicating the soil mixed with frozen chips of water. Meteorites can hit these soil particles – many times smaller than the width of human hair – up to 19 miles (30 km) from the impact site, depending on the size of the meteor. Particles can travel so far because the Moon has low gravity and no air to slow things down: "So each time you have one of these effects, a very thin layer of ice grains spreads over the surface exposed to the heat of the Sun and the cosmic environment, and ultimately sublimated or lost to other environmental processes, "said Dana Hurley, a planetary scientist at the John Hopkins University of Applied Physics Laboratory in Lorel, Maryland.

While it is important to keep in mind that even in darkened craters the water slowly sinks, water is likely to add, too, the paper writes. The ice comets that hit the moon, plus the solar wind, can load it as part of the global water cycle; this is something scientists are trying to understand. Moreover, it is not clear how much water there is. Whether it sits only in the upper layer of the moon's surface or extends deep into the moon's crust, do scientists wonder?

Anyway, the top layer of polar crater floors is being processed for thousands of years, according to Farrell, Hurley and their team. Therefore, the weak freezes that scientists have found on the poles using instruments such as the LAMP tool can be only 2000 years instead of millions or billions of years, as some might expect. , "We can not think of these craters as dead places," he noted.

To confirm the calculations of his team, Farrell said that a future instrument capable of detecting water vapor should detect over one Moon's surface of up to 10 cubic centimeter cubic centimeter molecules of water that were free from blows.

Good news for future exploration of the moon

For the upcoming science and research, the dispersion of water particles can be great news. This means that astronauts may not have to put themselves and their tools in the harsh environment of darkened crater floors to find water-rich soil – they could find it in sunny areas nearby.

"This study tells us that meteorites are doing some of the work for us and transporting material from the coldest places to some of the border areas where astronauts have access to it using a solar engine," Hurley said. "He also tells us that what we need to do is to climb the surface of one of these regions and get first-hand data of what's happening."

Reaching the moon will make it much easier to judge how much water is on the moon. Since identifying water from far away, especially in permanently shaded craters, is a tough job. The main way scientists find water is through remote sensing tools that can determine what chemical elements are made from the light they reflect or absorb. "But for that you need a light source," said Hurley. "And by definition, these permanently shaded regions do not have a strong one."

Understanding the Moon's Aquatic Environment

While NASA astronauts do not return to the moon to dig out some soil, or the agency sends new tools near the surface that can sink drifting water molecules, the team's theory of environmental meteorology research in the craters' shadows may to help break it off. in some mysteries around the moon's water. It has already helped scientists understand if the top surface water is new or ancient, or how it can migrate around the moon. Another thing that meteorological effects on crater floors could help explain is why scientists find thin-frozen stretches of land dissolved in reggolite or lunar soil instead of blocks of pure water ice.

While water issues are abundant, it is important to remember that Farrell says that only in the last decade scientists have found evidence that the Moon is not a dry, dead rock, as they have long imagined. LRO, with its thousands of orbits and a fifth-digit of backed-up scientific data (equivalent to about 200,000, high-definition, full-length movies transmitted online), is essential. Like the observation of the moon crater and satellite satellite (LCROSS), which revealed frozen water after deliberately crashing into the crater of Cabeus in 2009, and releasing a stream of saved material from the crater floor that included water.

"We suspected that there was water on the pillars and we learned for sure from LCROSS, but now we have evidence that there is water in the middle latitudes," Farrell says. "We also have evidence that water comes from micrometeoridal effects and we have frost measurements. But the question is how are all these water sources connected?

This is an issue with which Farrell and his colleagues are closer to the answer than ever before.

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