The Atacama Desert (Spanish: Desierto de Atacama) is a plateau in South America, covering a 600-mile (1,000 km) strip of land on the Pacific coast, west of the Andes mountains. It is, according to NASA, National Geographic and many other publications, the driest desert in the world.The Atacama occupies 40,600 square miles (105,000 km sq) in northern Chile, composed mostly of salt lakes (salares), sand, and felsic lava flows towards the Andes.
The Atacama Desert ecoregion, as defined by the World Wide Fund for Nature (WWF), extends from a few kilometers south of the Peru-Chile border to about 30° south latitude.To the north lies the Peruvian Sechura Desert ecoregion, whilst to the south is the Chilean Matorral ecoregion.The National Geographic Society, by contrast, considers the coastal area of southern Peru to be part of the Atacama Desert.It includes in this definition the deserts south of the Ica Region in Peru.To the east lies the less arid Central Andean dry puna ecoregion. The drier portion of this ecoregion is located south of the Loa River between the parallel Sierra Vicuña Mackenna and Cordillera Domeyko. To the north of the Loa lies the Pampa del Tamarugal.
The Atacama is sparsely populated, with most cities located along the Pacific coast.In interior areas, oases and some valleys have been populated for millennia, being the seat of the most advanced Pre-Columbian societies found in Chile. These oases have had little population growth and urban development, and have, since the 20th century, faced conflicts over water resources that are needed for the coastal cities and the mining industry.San Pedro de Atacama, at about 2,000 metres (7,000 ft) elevation, is a typical example. Its church was built by the Spanish in 1577. In pre-Hispanic times, before the Inca empire, the extremely arid interior was inhabited mainly by the Atacameño tribe. The tribe is noted for the construction of fortified towns called pucarás, one of which can be seen a few kilometers from San Pedro de Atacama.
The coastal cities originated in the 16th, 17th, and 18th centuries during the time of the Spanish Empire, when they emerged as shipping ports for silver produced in Potosí and other mines. During the 19th century the desert came under control of Bolivia, Chile, and Peru, and soon became a zone of conflict due to unclear borders and the discovery of sodium nitrate deposits. After the War of the Pacific, in which Chile annexed most of the desert, cities along the coast developed into international ports, and many Chilean workers migrated there. With the guano and saltpeter booms of the 19th century the population grew immensely, mostly due to immigration from central Chile.
In the 20th century the nitrate industry declined and at the same time the largely male population of the desert became increasingly problematic for the Chilean state. Mineworkers and mining companies came into conflict, and protests spread throughout the region.The Atacama desert again became a source of wealth from the 1950s onwards due to copper mining. The Escondida and Chuquicamata porphyry copper mines are located within the Atacama Desert.
Because of its high altitude, nearly non-existent cloud cover, dry air, and lack of light pollution and radio interference from the very widely spaced cities, the desert is one of the best places in the world to conduct astronomical observations. A new radio astronomy telescope, called ALMA, built by Europe, Japan, the United States, Canada and Chile in the Llano de Chajnantor Observatory officially opened on 3 October 2011.A number of radio astronomy projects, such as the CBI, the ASTE and the ACT, among others, have been operating in the Chajnantor area since 1999.
The European Southern Observatory operates two major observatories in the Atacama:
- The La Silla Observatory
- The Paranal Observatory, which includes the Very Large Telescope