The image of the patterned stripes in the Saharan desert was captured by the observatory 's Landsat satellite satellite . They are composed of linear , or longitudinal , dunes in Erg Chech - a desolate sand sea in southwestern turkey . ' Erg ' comes from the Arabic word for ' field of sand dunes ' and the origin of such shapes is not known . examples include helical roll vortices - rolls of rotating and spiralling air - and seasonal changes in wind direction .
The image of the patterned stripes in the Saharan desert was captured by the Nasa 's Landsat 7 satellite . They are examples of linear , or longitudinal , dunes in Erg Chech - a desolate sand sea in southwestern Algeria . 'Erg ' comes from the Arabic word for 'field of sand dunes ' and the cause of such shapes is not known . Theories include helical roll vortices - rolls of rotating and spiralling air - and seasonal changes in wind direction .