Tassili n’Ajjer National Park in southeastern Algeria. Part of the Sahara Desert, the park has a bone-dry climate with scant rainfall, yet does not blend in with Saharan dunes. Instead, the rocky plateau rises above the surrounding sand seas.
This image is made from multiple observations by the Landsat 7 satellite in the year 2000. It uses a combination of infrared, near-infrared, and visible light to better distinguish between the park’s various rock types. Sand appears in shades of yellow and tan. Granite rocks appear brick red. Blue areas are likely salts. As the patchwork of colors suggests, the geology of Tassili n’Ajjer is complex. The plateau is composed of sandstone around a mass of granite dating from the Precambrian.
Over billions of years, alternating wet and dry climates have shaped these rocks in multiple ways. Deep ravines are cut into cliff faces along the plateau’s northern margin. The ravines are remnants of ancient rivers that once flowed off the plateau into nearby lakes. Where those lakes once rippled, winds now sculpt the dunes of giant sand seas. In drier periods, winds eroded the sandstones of the plateau into “stone forests,” and natural arches. Not surprisingly, the park’s name means “plateau of chasms.”
The image shows the extraordinary landscape of the Tanezrouft Basin, one of the most desolate parts of the Sahara desert, in south-central Algeria. The region is known as ‘land of terror’ because of its lack of water and vegetation. As visible, this region is characterised by dark sandstone hills, steep canyon walls, salt flats (white), stone plateaus, sandstone outcrop patterns of concentric loops and sprawling seas of multi-storey sand dunes known as ‘ergs’. Erg Mehedjibat, which appears as a yellow bouquet of flowers (upper right), is made up of a cluster of small star dunes that grow upward rather than laterally.
(3 September 2005) Typhoon Nabi is featured in this image photographed by an Expedition 11 crewmember on the International Space Station, as it swirls in the Pacific Ocean, heading toward southern Korea and Japan. At the time this image was taken Typhoon Nabi was ~23N 133E with sustained winds ~100 knots, gusting to 120 knots.
Backdropped against clouds over Earth, the International Space Station is seen from Discovery as the two orbital spacecraft accomplish their relative separation on March 7, 2011 after 12 astronauts and cosmonauts worked together for over a week. During a post undocking fly-around, the crew members aboard the two spacecraft collected a series of photos of each other’s vehicle.