The Lunar Reconnaissance Orbiter (LRO) orbital probe unexpectedly discovered deposits of water ice at the moon's south pole in relatively warm craters. The research report was published in the Icarus journal, and the portal Phys.org briefly talks about it.
The discovery was made by analyzing data obtained by NASA's orbiting lunar probe. Light areas have been found inside the craters near the South Pole. Data on the surface temperature and the amount of light reflected from it helped to establish that they are cold enough for the presence of water ice.
"We found that the coldest parts of the moon's surface near its south pole are also the brightest," said study lead author Elizabeth Fisher of the University of Hawaii at Manoa. “They are much brighter than they should be if we assume that the reflection is only from the ground. This indicates the presence of ice."
In the images, the deposits appear thin and spotty. They mix with the surface layer of the soil, dust and small rocks - regolith. Scientists say these areas don't look like a frozen pond or ice rink. Rather, they are covered with frost.
The discovery proved that ice on the Moon is concentrated not only in "cold traps" - constantly shaded areas located inside craters and receiving no direct sunlight. It can also persist for a long time in relatively warm craters at the South Pole.