Mysterious Moon Swirls May Be Caused By A Lunar Recipe Of Lava And Magnetized Rocks

hero nasa moon swirls
Scientists have come up with a new theory about what is causing mysterious swirls on the Moon’s surface. The latest theory involves underground lava, magnetized rocks, and magnetic anomalies.

Lunar swirls have baffled astronomers and scientists since they were first discovered in the 1600s. Scientists believe these light-colored regions, such as the well-known Reiner Gamma swirl, could hold the answers to many questions about conditions on the Moon, as well as other airless worlds throughout the solar system. Now, a new study from a group of scientists from Stanford University and Washington University have theorized an explanation to the mysterious swirls.

The study includes new modeling and spacecraft data that shed light on the swirly mystery. New data indicated rocks in the swirls are magnetized, with those same rocks deflecting or redirecting solar wind particles that constantly affect the Moon. The neighboring rocks end up taking the brunt of the impact. After a period of time, the neighboring rocks become darkened by chemical reactions caused by the collisions, while the swirls remain light colored. However, it still leaves the question of how the rocks got magnetized in the first place, since the Moon does not have a magnetic field today.

nasa moon swirl monochrome
NASA's Lunar Reconnaissance Orbiter Wide Angle Camera’s monochrome image of the Reiner Gamma swirl.

“Impacts could cause these types of magnetic anomalies,” remarked Michael J. Krawczynski, an associate professor at Washington University in St. Louis, and co-author of the new study. “But there are some swirls where we’re just not sure how an impact could create that shape and that size of thing.”

This led Krawczynski and the other scientists to think the cause for magnetization being caused by something local. Another theory presented by the new study is the Moon having lava underground, which is cooling slowly in a magnetic field and creating the magnetic anomaly. Krawcyznski and first author Yuanyuan Liang ran tests to measure the effects of different combinations of atmospheric chemistry and magmatic cooling rates on a mineral called ilmenite in order to determine if it would produce a magnetizing effect.

“Earth rocks are very easily magnetized because they often have tiny bits of magnetite in them, which is a magnetic mineral,” Krawczynski explained. “A lot of the terrestrial studies that have focused on things with magnetite are not applicable to the Moon, where you don’t have this hyper-magnetic mineral.”

However, ilmenite is abundant on the Moon, and can react and form particles of iron metal, which can also be magnetized under the right conditions, according to a post on Washington University in St. Louis’ website. Liang remarked that the smaller grains they were working with seemed to create stronger magnetic fields because of the surface to area to volume ratio is larger for the smaller grains compared to the larger grains. Liang added with more exposed surface area, it was easier for the smaller grains to undergo the reaction.

“Our analog experiments showed that at lunar conditions, we could create the magnetizable material that we needed. So, it’s plausible that these swirls are caused by subsurface magma,” remarked Krawczynski.

It may not be much longer before NASA will have more answers to the mysterious lunar swirls, and possibly verify whether the new study is correct. The Lunar Vertex lunar lander, part of the Artemis program, will land within the Reiner Gamma, where it will conduct complementary investigations from the lander and from a small rover that will explore just over a mile of the 43-mile wide surface feature.