Template:POTD/2007-02-18
Erg Chebbi, the sole Saharan erg in Morocco. An erg is a large, relatively flat area of desert covered with wind-swept sand with little to no vegetation cover. Approximately 85% of all the Earth's mobile sand is found in ergs that are larger than 32,000 km². Individual dunes in ergs typically have widths, lengths, or both dimensions greater than 500 m.
Ergs can be found where an atmosphere capable of significant wind erosion acts on the surface for a significant period of time, creating sand and allowing it to accumulate. Today at least three bodies, apart from Earth, are known in the solar system to feature ergs on their surface: Venus, Mars and Titan.Photo credit: Rosa Cabecinhas and Alcino Cunha