Bright spots on our moon could be frost, says NASA
While the famed bright spot on dwarf planet Ceres got lots of attention in the past few years, it turns out that there are a few bright spots a bit closer to home. Analyzing data from NASA's Lunar Reconnaissance Orbiter (LRO), researchers have spotted bright areas on our own moon which, they say, are likely being caused by frost. If they're right, the frozen water particles could be as old as the solar system itself and could provide clues about ancient water delivery to the moon and Earth.
To reach its conclusion, the team looked at data provided by LRO's Diviner instrument, which collects temperature data, and compared it to brightness readings that were provided by the craft's Lunar Orbiter Laser Altimeter. They found that the coldest areas, which were found by the moon's south pole, were also very bright. The logical conclusion is that the brightness is being caused by ice particles.
While the idea of ice skating on the moon one day might appeal, the researchers are mostly seeing signs of patchy frost with ice particles possibly mixed in with lunar soil. The frost is appearing in what's known as cold traps – permanently dark areas found inside deep craters where the temperatures never climb above -260° F (-163° C). Last year, researchers also postulated that the same ice-storing process might be at work on Ceres. And the new findings match up to an analysis that was done in 2015 using data from the Lyman-Alpha Mapping Project (also aboard LRO) which measures reflected starlight and the UV glow of hydrogen.
Even more intriguing than finding the presence of frost on the moon is working out just how old it is and where it comes from.
"If the water was delivered by icy comets or asteroids, it could be as ancient as the solar system and could mark the early delivery of water to Earth and the moon," says NASA. "But if the water was produced by chemical reactions driven by the solar wind, it is much more recent. Or both may be true. There could be eons-old ice deposits buried below ground and newer water at the surface."
Future research will be aimed at sorting out more about the frosty regions and their origins.
The findings are detailed in the video below and have been published in the journal Icarus.