At first glance, this beautiful swirling view appears like clouds above a large body of water or possibly the eddies of ocean currents. Surprisingly, this is a desert, the Kavir desert (Dasht-e Kavir – literally ‘desert of salt-marsh’) in Iran, and the image was taken by one of the astronauts on the International Space Station.
While a quick look at Google Maps (see image below) shows that most of the region does appear to be sand-colored brown from space, there are regions with blue tints due to the folds and layers in the exposed surfaces, and the image is actually just a small part of the 77,600 square kilometer (30,000 sq mile) desert. It’s a bit difficult to get a sense of scale in the top image since there are no fields or roads to provide a reference, but the width of the image is about 105 kilometers (65 miles).
There is some water in this area, however. In the center of the NASA image is a dark s-shaped region is a lake and a small river snakes across the bottom of the image. The irregular, light-toned patch just left of the lake is a sand sheet thin enough to allow the underlying rock layers to be detected.
Source: NASA Earth Observatory