* Astronomy

 Mysterious African 'Fairy Circles' Stump Scientists

In the sandy desert grasslands of Namibia in southern Africa, mysterious bare spots known as "fairy circles" will form and then disappear years later for no reason anyone can determine. A new look at these strange patterns doesn't solve the wistful mystery but at least reveals that the largest of the circles can linger for a lifetime.
Small fairy circles stick around an average of 24 years, while larger ones can exist as long as 75 years, according to research detailed today (June 27) in the journal PLoS ONE. Still, the study sheds little light on why the circles form, persist and then vanish into the landscape after decades.
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Title: The Foraging Tunnel System of the Namibian Desert Termite, Baucaliotermes hainesi.
Authors: Walter R. Tschinkel

Many termites do not build mounds that show above ground, but construct entirely subterranean nests, with tunnels to the surface. The best known of these is the African harvester termite, Hodotermes mossambicus, largely thanks to occasional subterranean encounters during the digging of trenches for construction (Coaton and Sheasby 1975; Hartwig 1963, 1965). These encounters revealed that nests are located an average about 1.4 m below ground, but can be as shallow as a few cm or as deep as 6.7 m. Large passages connect these subterranean nest to each other, and smaller ones give the termites access to the surface where they dump excavated soil and forage for grass. Foraged grass is first placed into small, superficial chambers for later transport to the nests and consumption.

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