Sand Dunes, Saudi Arabia

Sand Dunes, Saudi Arabia

Courtesy of NASA/JPL/UCSD/JSC

http://photojournal.jpl.nasa.gov/catalog/PIA11069


This image in Saudi Arabia is on the edge of the Rub' al-Khali or Empty Quarter. The Rub' al-Khali is a vast desert in southern Arabian Peninsula covering about 402,000 square kilometers of Saudi Arabia, Yemen, Oman, and the United Arab Emerates. It is the largest contineous expanse of sand, one of the driest regions of the world, virtually uninhabited and largely unexplored.

The dark circles are pivot irrigation systems often used in arid regions to provide productive farmland. A well in the center of the circle provides water to the sprinklers that pivot around the center. The diamenter of the circles can range from a few hundred meters to almost two kilometers.