Scientists baffled by mysterious 'fairy circles' found at hundreds of sites across the world

The interplay of natural forces produces intricate patterns and structures that prevail around the world’s geography. One form of these patterns is “fairy circles,” fascinating vegetation patterns formed by the forces of air and water. Previously, fairy circles were thought to exist only in Africa’s Namib Desert and Australia's Pilbara region. Conversely, a 2023 study published in the journal Proceedings of the National Academy of Sciences revealed that this pattern is prevalent across 263 locations in areas from Madagascar to southwestern Asia. 

Fairy circles are unexplained geological mysteries, named for their resemblance to the circular formation of mushrooms known as “fairy rings,” according to Scientific American. They are not some serrated contours or jagged round shapes, but rather, patches of barren land, devoid of vegetation, and dispersed like polka dots.

To investigate several locations for these dotty formations, researchers used an AI model. They trained the AI to scour through more than half a million satellite images of dryland regions and look for patterns that matched fairy circles. This AI worked just like a human brain, forming the neural network of all the images that were inputted into it, per CNN.

More than 15,000 satellite images taken over Namibia and Australia were inputted into AI’s brain. Half of the images showed fairy circles, and half did not. The researchers also inserted satellite views of nearly 575,000 plots of land around the world, each measuring about 2.5 acres, into the AI. The AI’s neural network scanned vegetation in those images and identified repeating circular patterns that resembled fairy circles.

Then they manually sorted out the output results. “We had to manually discard some artificial and natural structures that were not fairy circles based on photo-interpretation and the context of the area,” Emilio Guirado, a data scientist with the Multidisciplinary Institute for Environmental Studies at the University of Alicante in Spain told CNN.

The results revealed that fairy circles were found in 263 arid spots distributed across Africa, Madagascar, Midwestern Asia, and central and Southwest Australia. The researchers then analyzed these locations to observe any common characteristics that could provide insights into the formation process of fairy circles. Interestingly, they did find some common soil and climate factors such as low nitrogen and low or negligible rainfall. “Because the study used an observational approach, the results can’t pinpoint the mechanism behind the patterns,” said Guirado, per Scientific American.

Folklore has various myths associated with these fairy circle patterns. The Himba people of Namibia believe that fairy circles are the “footprints of the gods”, made by their ancient ancestor Mukuru, whereas others believe that a dragon who lives in the cracks beneath the earth has poisonous breath that burns up the plants. But as findings suggested, the cause behind these mysterious circles could simply be “low moisture in the soil.”

However, researchers considered other possibilities as well. The cause of these polka dots could be plant toxins or gaseous emissions from below the ground, but these factors were quickly ruled out. Only two theories seemed to give a potential explanation for the phenomenon. One theory, proposed by ecologist Norbert Jürgens, said that these circles could form as a result of colonies of termites hiding underground. They chew through the plant roots, making the plants disappear and leaving barren patches on the ground.

Another theory, by ecologist Stephan Getzin of the University of Göttingen in Germany, proposed that the pattern could form as a result of the ecosystem’s self-organization process. But neither of these theories had enough evidence for support. So, the mystery behind these fairy circles remained unsolvable. “There is no universally agreed definition of what a fairy circle is,” Fernando Maestre, a University of Alicante ecologist told Scientific American.

Besides, none of Getzin’s descriptions fit the fairy circles that were discovered. Getzin previously described these circles as having a spatially periodic pattern. He proposed that these circles form a hexagonal formation in which one circle is a focal point, positioned in the center of six others and at approximately the same distance from each. But this wasn’t the case with the fairy circles spotted recently. Getzin even added that the latest fairy circles discovered were not the “true fairy circles,” and that the true ones were only in Namibia and Australia.

Walter Tschinkel, a Florida State University biologist who has studied fairy circles, also thought the same, “You’d have to convince me that they’re fairy circles; they’re not regular enough. These are just gaps in vegetation. In arid zones, vegetation is rarely a uniform carpet, it always consists of a lumpy distribution.” He hoped the findings would open the door to novel research on the patterns in these new locations.