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.

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.

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.

Lunar outgassing

Outgassing events in which volatiles are vented from deep in the lunar interior to the surface, specifically, radon, nitrogen, carbon monoxide, and carbon dioxide, may be the result of low level volcanic or tectonic events on the moon, and are hypothesized to be the source of the tenuous lunar atmosphere.

Knowing when and where these events occur may help us understand more about lunar tectonics and how the moon’s atmosphere was formed.

Carbon and Nitrogen are both vital elements which will have to be imported from earth or from carbonaceous asteroids. If outgassing events can be predicted it may be possible to utilize this valuable resource.

The Alpha Particle Spectrometer aboard Lunar Prospector was designed to detect these events by tracking the alpha particles emitted during the decay of radon 222 and polonium 226 (two increments immediately preceded by Ra226 in the decay series of U238). The APS data was obscured by solar activity during the mission, but may be viewable once the effects of solar activity have been filtered out. This task has not been done.

Ground Penetrating Radar studies have been made with wavelengths penetrating 10-20 meters via the Arecibo and Green Bank radio observatories, but deeper and higher resolution scans are likely needed to detect further sub-surface gas pockets. Radar dark areas in the 70cm band, termed “halos”, have been detected around many impact craters. An especially large halo has been detected around Aristarchus crater and encompasses much of the Aristarchus plateau. Aristarchus is the major source of recent outgassing events detected via Radon 222 activity. It has been suggested that the Aristarchus halo may be the result of subsurface ice deposits, but this has not been confirmed. Aristarchus is known to be an active outgassing site[1].

Many observers have reported witnessing so called “Transient lunar phenomena” including many amateur Astronomers. The crew of Apollo 11 reported observing a TLP at the crater Aristarchus.

Although the Moon is relatively inert geologically, the lunar atmosphere continues to be replenished by lunar outgassing events.

https://lunarpedia.org/index.php?title=Lunar_outgassing

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