The Moon’s south pole region is home to some of the most extreme environments in the solar system: it’s unimaginably cold, massively cratered, and has areas that are either constantly bathed in sunlight or in darkness.
The Moon’s south pole region is home to some of the most extreme environments in the solar system: it’s unimaginably cold, massively cratered, and has areas that are either constantly bathed in sunlight or in darkness. This is precisely why NASA wants to send astronauts there in 2024 as part of its Artemis program.
The most enticing feature of this southernmost region is the craters, some of which never see the light of day reach their floors. The reason for this is the low angle of sunlight striking the surface at the poles. To a person standing at the lunar south pole, the Sun would appear on the horizon, illuminating the surface sideways, and, thus, skimming primarily the rims of some craters while leaving their deep interiors in shadow.
As a result of the permanent darkness, NASA’s Lunar Reconnaissance Orbiter (LRO) has measured the coldest temperatures in the solar system inside these craters, which have become known as perfect environments for preserving material like water for eons. Or so we thought.
It turns out that despite temperature that dips to -388 degrees Fahrenheit (-233 Celsius) and can presumably keep frost locked in soil virtually forever, water is slowly escaping the topmost, super thin layer (thinner than the width of a red blood cell) of the Moon’s surface. NASA scientists reported this finding recently in paper in the journal Geophysical Research Letters.
Read more at NASA/Goddard Space Flight Center
Image: This is a permanently-shadowed crater on the Moon. (Credit: NASA's Goddard Space Flight Center)
