Water ice was found on the moon. The ice was locked in a shadow at the moon's north and south poles, and had seemingly survived for millions of years.
There was a new mystery to the discovery of water ice. The polar craters are not protected from solar wind, waves of charged particles that gush out of the sun at hundreds of miles a second. The wind should have destroyed the ice on the moon long ago, according to a planetary scientist at the University of Hawaii. The moon does not have a magnetic shield to protect it from the charged particles.
How did the moon's polar ice survive? A new map of the moon's south pole may provide an answer.
Scientists from the University of Arizona presented a map of magnetic anomalies on the lunar surface at the conference. According to NASA, these anomalies were first detected during the Apollo 15 and 16 missions in the 1970s, and are thought to be remnants of the moon's ancient magnetic shield.
Several large polar craters that sit in permanent shadow may contain ancient ice deposits. According to the researchers, these anomalies may be serving as tiny magnetic shields that protect lunar water ice from the constant bombardment of solar wind.
Lon Hood, a planetary scientist at the University of Arizona, told Science that the anomalies could be significant in shielding the permanently shadowed regions.
The authors combined 12 regional maps of the lunar south pole, which were originally recorded by the Kaguya spacecraft. The magnetometer was included in the science tools and could detect pockets of magnetism on the lunar surface.
At the lunar south pole, there are at least two permanently shadowed craters that are covered in magnetic anomalies. The researchers said in their presentation that the anomalies could be used to protect the solar wind. The research has not been published in a peer-reviewed journal. That could be the key to the moon&s long-term water ice.
No one knows where the magnetic anomalies on the moon came from. A paper written by Hood in the Encyclopedia of Lunar Science theorizes that they date back to when the moon had a magnetic field of its own. When large, iron-rich asteroids crashed into the moon, they may have created magma surfaces that slowly cooled over hundreds of thousands of years, becoming permanently magnetized by the moon's magnetic field.
The lunar south pole has pitch-dark ice deposits. The Artemis missions plan to land astronauts at the lunar south pole in order to establish a permanent base there. Studying the ice deposits in this region could show how they were created.
Science has more about the ancient magnetic field.
It was originally published on Live Science.
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