Today, we are still working to understand many of the features we see on that Moon. One of the oddest features is light and dark patterns in the lunar terrain. Called lunar swirls, these patterns are located where there are magnetic anomalies – places where a magnetic field can be found for unknown reasons. Most of the time, there is no correlation between these colored patterns and the shape of the landscape they sprawl across. That said, a new paper led by Deborah Domingue of the Planetary Science Institute finds that two lunar swirls actually do follow the landscape, with bright regions being lower and darker regions being higher.

In general, bright regions of the swirls are thought to be places where magnetic fields protect the surface material from the solar wind. This wind of high-energy particles will darken moon dust over time, creating the darker parts of these swirls.

‘In general,’ however, doesn’t mean this is always the case, and in the two exceptions this paper identifies, researchers need to ask if the swirls may have other explanations. As Domingue puts it: The question becomes how much do we understand the processing of the lunar surface and the migration of fine-grained materials. Swirls are not only a place to test our ideas on space weathering of the surface but of the efficiency of dust migration across the surface. If we are going to have long-term installations on the surface of the Moon, how do we protect against issues that fine-grained dust present to robots, habitats, space suits, and other machinery, let alone on the health and safety of humans present on the surface for long durations?

To really understand what is going on, we’re going to need to go explore these swirls more closely, by rover, robot, or human, but that kind of exploration is still years away, so for now, we shall stare at pretty pictures and try to pry out science.

More Information

PSI press release

“Topographic Correlations Within Lunar Swirls in Mare Ingenii,” Deborah Domingue et al., 2022 March 2, Geophysical Research Letters