In the latest chapter of \u201cThe Mystery of the Lunar Swirls,\u201d planetary scientists have a new theory to explain these odd markings on the Moon\u2019s surface. It invokes underground magmas and strange magnetic anomalies.<\/p>\n
<\/p>\n Lunar swirls are sinuous features that appear much lighter than the surrounding landscape. They extend for hundreds of kilometers and nobody\u2019s quite sure why they exist. No astronaut has visited one of these weird regions, but that hasn\u2019t stopped scientists from speculating based on images and magnetic field measurements. \u201cImpacts could cause these types of magnetic anomalies,\u201d said Michael J. Krawczynski, an associate professor of earth, environmental, and planetary sciences in Arts & Sciences at Washington University in St. Louis. Krawczynski points out that meteorites supply iron-rich material to areas on the Moon\u2019s surface. However, these swirls exist in regions that aren\u2019t necessarily disturbed by meteorites. So, what else could explain the swirls?<\/p>\n \u201cAnother theory is that you have lavas underground, cooling slowly in a magnetic field and creating the magnetic anomaly,\u201d said Krawczynski, who, along with post-doctoral student Yuanyuan Liang, designed experiments to test this explanation. They measured the effects of different atmospheric chemistries and magmatic cooling rates on a mineral called ilmenite and found that under certain conditions, cooling subsurface lavas could be causing the ghostly lunar swirls.<\/p>\n Despite the fact that more than a dozen people have walked on the Moon, nobody visited a lunar swirl or picked up samples of their dust. That left Earth-bound planetary scientists to use Earth analogs for Moon rocks to understand lunar magnetism. \u201cEarth rocks are very easily magnetized because they often have tiny bits of magnetite in them, which is a magnetic mineral,\u201d Krawczynski said. \u201cA lot of the terrestrial studies that have focused on things with magnetite are not applicable to the Moon, where you don\u2019t have this hyper-magnetic mineral.\u201d<\/p>\n So, the research team turned to ilmenite as their test material. It\u2019s a titanium-oxide mineral with a weak magnetic signal. Ilmenite exists all over the Moon. It readily reacts to form magnetizable iron metal particles. \u201cThe smaller grains that we were working with seemed to create stronger magnetic fields because the surface area to volume ratio is larger for the smaller grains compared to the larger grains,\u201d Liang said. \u201cWith more exposed surface area, it is easier for the smaller grains to undergo the reduction reaction.\u201d<\/p>\n Interestingly, planetary scientists have seen a similar reaction creating iron metal in lunar meteorites in samples from the Apollo missions. The difference, however, is that those samples came from surface lava flows. Krawczynski and Liang\u2019s study focused on the types of magma that cooled underground.<\/p>\n \u201cOur analog experiments showed that at lunar conditions, we could create the magnetizable material that we needed. So, it\u2019s plausible that these swirls are caused by subsurface magma,\u201d said Krawczynski. \u201cIf you\u2019re going to make magnetic anomalies by the methods we studied, then the underground magma needs to have high titanium.\u201d<\/p>\n Those mysterious dust patterns aren\u2019t just there by accident. They contain clues to the processes that shaped the lunar surface. In addition, if magnetism is involved in their formation, that says something about magnetism on the Moon as a whole.<\/p>\n Until astronauts can get to the Moon to study these swirls for themselves, the ilmenite experiment offers a good way to test the underground magma idea from afar, according to Krawczynski. Of course, it would be nice to get actual samples of underground rocks on the Moon, but that\u2019s going to have to wait. \u201cIf we could just drill down, we could see if this reaction was happening,\u201d he said. \u201cThat would be great, but it\u2019s not possible yet. Right now, we\u2019re stuck with the surface.\u201d<\/p>\n Studies like Krawczynski and Liang\u2019s will be quite useful when NASA sends future lunar missions to the surface. There\u2019s a whole rover project, part of a mission called Lunar Vertex, planned to study Reiner Gamma. That\u2019s one of the Moon\u2019s better-known swirls. Vertex should launch this year and is a predecessor to the larger return to the Moon NASA plans for later this decade. That mission could confirm whether or not swirls are magnetic field-related. If not, then there\u2019s something else going on at Reiner Gamma and other swirl sites.<\/p>\n Moon \u201cSwirls\u201d Could be Magnetized by Unseen MagmasUsing Earth-based Geological Principles to Understand Lunar Swirls<\/h3>\n
Why Study Swirls on the Moon?<\/h3>\n
![\"Artist\u2019s](\"https:\/\/www.universetoday.com\/wp-content\/uploads\/2024\/07\/LunarVertex_SpaceWeb_0-1024x683.jpg\")
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