The driest non-polar desert on Earth, with stations that have never recorded a drop of rain
Some riverbeds appear to have been dry for over 100,000 years
Geography · Physical geography
The Atacama Desert
Chile — the Pacific coast of northern Chile, with edges in Peru, Bolivia and Argentina
The driest non-polar desert on Earth, a thousand-kilometre strip between the Andes and the Pacific where some weather stations have never recorded rain. Squeezed by a double rain shadow and cooled by the Humboldt Current, it is so dry and so clear that the world's great optical and millimetre telescopes are built there, and NASA uses it to rehearse the search for life on Mars.
How to spot them
- ▸The driest desert outside the poles — parts of it have no recorded rainfall at all
- ▸Quiz clue: 'Humboldt Current', 'ALMA', 'Chuquicamata', 'saltpetre', 'Chinchorro mummies'
- ▸Home to the Very Large Telescope and the world's largest millimetre-wave array
- ▸Its nitrate deposits made fortunes, then a war, then were undercut by a German chemical process
Key facts
Dry because it sits between two rain shadows and beside a cold current
The Andes block Atlantic moisture, the Chilean Coast Range blocks the Pacific, and the Humboldt Current suppresses evaporation
Its skies are so clear and stable that the European Southern Observatory built its flagship telescopes there
The Very Large Telescope at Paranal and the Extremely Large Telescope on Cerro Armazones
A 66-antenna millimetre-wave array sits on the Chajnantor plateau at 5,000 metres
ALMA, the Atacama Large Millimeter/submillimeter Array
NASA and ESA test Mars rovers and life-detection instruments on its soils
The Viking landers' life-detection experiments were rehearsed on its ground in the 1970s
Its nitrate fields made Chile rich, triggered a war with Peru and Bolivia, then collapsed
The War of the Pacific, 1879–83; the Haber–Bosch process later made synthetic nitrogen cheaper
Its mummies are older than any in Egypt
The Chinchorro people were artificially mummifying their dead by about 5000 BC
Quick-fire facts
- •It runs about 1,000 km down the Pacific coast of northern Chile, covering some 105,000 km²
- •Some weather stations there have never recorded rainfall; average annual rain in parts is around 1–3 mm
- •Its aridity comes from a double rain shadow plus the cold Humboldt Current offshore
- •Paranal (the VLT), Chajnantor (ALMA) and Cerro Armazones (the ELT) are all in or beside it
- •Chuquicamata and Escondida, among the world's largest copper mines, lie within it
- •Its sodium nitrate 'caliche' was the world's fertiliser and explosives supply until Haber–Bosch
- •The Chinchorro mummies of its coast, from around 5000 BC, are the oldest deliberately mummified human remains known
- •Common misconception: it is not the driest place on Earth outright — the McMurdo Dry Valleys of Antarctica are drier, and it is not lifeless: fog-fed lichens, cacti and microbes survive in it
Drill it — 8 cards
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Sources
- European Southern Observatory — ALMA — Atacama Large Millimeter/submillimeter Array
- European Southern Observatory — Paranal Observatory