These bizarre circles have baffled scientists for years. Now we may know what they are.
See these weird circles? Do you know what they are?
They're big, circular patches of bare ground surrounded by plants. When I say big, I mean big — they can get up to 50 feet in diameter and can be seen for miles along desert grasslands.
They're called fairy circles.
"Ohhhh it's fairies! Case closed!" you might be saying.
But, no, I'm sorry. As much as we all love Tinker Bell, fairies just aren't an accepted scientific hypothesis, no matter how much we'd like them to be.
Fairy circles only appear in certain, special places like Namibia. But recently, they've been spotted in Australia.
Scientists have known about Namibia's fairy circles since about the 1920s. But as of 2014, we know they appear in the dry, remote Pilbara region of Western Australia, too.
(If you want to have a bit of fun, they're visible on Google Earth in Namibia and in Western Australia.)
Fairy circles have baffled scientists for a long time.
Some people thought they might have been created by termites, or carbon monoxide from deep within the Earth, or plants poisoning the ground. Tour guides in Africa have apparently been telling people it's because of a mythical dragon's incredibly awful breath.
But one idea seems pretty promising: It has to do with water, or a lack thereof.
Dr. Stephan Getzin of the Helmholtz Centre for Environmental Research in Germany and other colleagues analyzed the soil in the Australian circles.
Here's what they think happens:
When a bare, plant-less patch of soil dries out, the sun bakes it into a hard, impenetrable crust. Once the crust is formed, any rain that does fall on it either runs out to the edges or just evaporates. At the edges, however, the plants prevent the soil from baking as much, so the water drains into the dirt.
It's a kind of natural balancing act. Over time, these circles naturally grow and shrink as conditions change.
Getzin did caution that the process in Namibia may be different, however, because Namibia has a different, sandier kind of soil, but that fairy circles in both areas depend on water to form.
"The details of this mechanism are different to that in Australia," Getzin explains in a press release. "But it produces the same vegetation pattern because both systems of gaps are triggered by the same instability."
Getzin believes more undiscovered fairy circles may lie in other remote parts of the world.
If he is right and these fairy circles really are tied to water shortages and cycles, it's possible that these magical circles will spring up in other dry, desert areas as climate change alters weather patterns.
It's just a cool reminder about how much there is still left to discover in the world around us and how much we can learn about what the Earth is telling us about its needs if we just know how to understand the signs.