Solar Wind Leaves 'Sunburn' Scars on the Moon

People on Earth who've gotten sunburns are familiar with the sun's powerful rays — but the moon suffers from sunburn, too. 

Some regions of the lunar surface exhibit a distinctive pattern of darker and lighter swirls. Using NASA's ARTEMIS mission — which stands for Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun — astronomers have revealed new clues about the origin of these swirls. 

The sun releases a constant flow of charged particles known as solar wind into space. While Earth's natural magnetic field deflects solar-wind particles, the moon has a weaker magnetic field, leaving some areas of the lunar surface exposed to the sun's damaging radiation, according to a statement from NASA. 

Related: This NASA Video Tour of the Moon in 4K Is Simply Breathtaking

Unlike Earth, the moon doesn't have a global magnetic field. Rather, magnetized rocks near the lunar surface create small, localized magnetic fields that extend only a short distance, according to the statement. 

"The magnetic fields in some regions [of the moon] are locally acting as this magnetic sunscreen," Andrew Poppe, a scientist at the University of California, Berkeley, said in the statement.

The Reiner Gamma lunar swirl photographed by NASA's Lunar Reconnaissance Orbiter is an example of the moon's "sunburn." (Image credit: NASA LRO WAC science team)

These small "bubbles" of protection deflect some of the damaging solar-wind particles. As a result, light-colored swirls form in the shielded areas. However, the bordering areas become noticeably darker. 

"You know, sometimes you put on sunscreen and you miss a tiny little bit and then you have a really bright red spot on you your skin where you missed it," Poppe said in a NASA video explaining the discovery. "That's, in some ways, the analogy for the region of the moon that is extra exposed."

The team hopes the findings will help protect astronauts from the harmful effects of radiation during future missions to the moon. Although the moon's crustal magnetic fields may not be strong enough alone to protect astronauts, it may be possible to create a stronger magnetic field artificially, Poppe said in the video. 

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Samantha Mathewson
Contributing Writer

Samantha Mathewson joined as an intern in the summer of 2016. She received a B.A. in Journalism and Environmental Science at the University of New Haven, in Connecticut. Previously, her work has been published in Nature World News. When not writing or reading about science, Samantha enjoys traveling to new places and taking photos! You can follow her on Twitter @Sam_Ashley13.