Strange circles' from the sky fall

On the sandy desert in Namibia of southern Africa, many 'fairy circles' formed and disappeared after a few years that no one could explain. The lifetimes of these circles are not the same, but can last as long as a lifetime.

Some small circles exist for an average of 24 years, while the circle is larger than 'live' for 75 years, a study published in PloS ONE magazine. This study also speaks very little why those circles were formed, existed then disappeared after several decades.

Biologist Walter Tschinkel of Florida State University, began studying the mysterious circles in Namibia since 2005. Thousands of strange circles exist on the red sandy area. Shortly after the circle formed, the grass also grows along the edge of the circle.

Circles with grass borders around.(Source: Livescience)

There are very few scientists who have studied the first circles , because they are located in very remote places, up to 180km from the nearest village. This is an arid region, where antelopes, African ostriches, newspapers and some other large animals often roam.

Initially, Tschinkel hypothesized that circles were formed around the mouths of underground termite nests. But after digging, Tschinkel found no evidence of the termite nest below. Other explanations, such as the nutritional differences of dead soil or grass seed in areas with toxic vapors from the soil, have been tested to be incorrect.

A lot of strange circles on a large area.(Source: Livescience)

Up to now, even the life cycle of these circles is very little known. With the help of the nature conservation team, satellite images and aerial photographs, Tschinkel was able to compare images taken between 2004 and 2008. He found that the circles were relatively stable. The diameter of the smallest circle is nearly 2m, of the largest circle is nearly 12m. The wind did not stop blowing in the dry land, causing many circles to lose their grass edges, so they looked like ghost circles. Tschinkel estimates that the life of these circles is between 30 and 60 years.

When very few people studied these circles, there was no funding for research, so Tschinkel thought that the first circles were unknown.

Reference: Livescience