July 20, 2015 — Located near the western edge of the Sahara Desert, the Eye of the Sahara is a feature that resembles a large eye when viewed from space. Also known as the Richat Structure or Guelb er Richat, the Eye is a symmetrical dome of eroded sedimentary and volcanic rock. The outermost rings measure approximately 40 km (25 miles) across. Persistent northeasterly winds keep much of the dome free from sand, exposing the various layers of rock. The circular feature was initially interpreted to be an asteroid impact structure, but most scientists have now concluded that it was caused by geologic uplift.
About the image
The Eye of the Sahara image is a mosaic of four different Landsat 8 scenes that show the geologic feature in false color. By blending visible and infrared wavelengths (bands), scientists can enhance the visibility of the various rock layers in contrast to the surrounding sand (yellow to white).
The Eye is the latest example of a series of images prepared each week by the USGS Earth Resources Observation and Science (EROS) Center — the Image of the Week.
Additional Landsat images selected for their artistic qualities can be found in USGS collections of Earth as Art. A new Earth as Art 4 collection will be available in early fall.
Landsat is a joint effort of USGS and NASA. NASA develops remote-sensing instruments and spacecraft, launches the satellites, and validates their performance. USGS develops the associated ground systems and, after launch, operates the satellites, as well as managing data reception, archiving, and distribution. Since 2008, all Landsat data are freely available to anyone on Earth.
The latest technical information about Landsat can be found at the USGS Landsat Missions website.
Landsat users can interactively explore the Landsat archive on the improved LandsatLook Viewer.