Mount Everest – also called Sagarmatha (Nepali: सगरमाथा), Chomolungma or Qomolangma(Tibetan: ཇོ་མོ་གླང་མ) or Zhumulangma (Chinese: 珠穆朗玛峰 Zhūmùlǎngmǎ Fēng) – is thehighest mountain on Earth, as measured by the height above sea level of its summit, 8,848 metres (29,029 ft). The mountain, which is part of the Himalaya range in High Asia, is located on the border between Sagarmatha Zone, Nepal, and Tibet, China.
In 1856, the Great Trigonometric Survey of India established the first published height of Everest at 29,002 ft (8,840 m), although at the time Everest was known as Peak XV. In 1865, Everest was given its official English name by the Royal Geographical Society upon recommendation of Andrew Waugh, theBritish Surveyor General of India at the time. Waugh was unable to propose an established local name because Nepal and Tibet were closed to foreigners at the time, although Chomolungma had been in common use by Tibetans for centuries.
The highest mountain in the world attracts climbers of all levels, from well experienced mountaineers to novice climbers willing to pay substantial sums to professional mountain guides to complete a successful climb. The mountain, while not posing substantial technical climbing difficulty on the standard route (other eight-thousanders such as K2 or Nanga Parbat are much more difficult), still has many inherent dangers such as altitude sickness, weather and wind. By the end of the 2008 climbing season, there had been 4,102 ascents to the summit by about 2,700 individuals. Climbers are a significant source of tourist revenue for Nepal, whose government also requires all prospective climbers to obtain an expensive permit, costing up to US$25,000 per person. Everest has claimed 210 lives, including eight who perished during a 1996 storm high on the mountain. Conditions are so difficult in the death zone that most corpses have been left where they fell. Some of them are visible from standard climbing routes.
In 1856, Andrew Waugh announced Everest (then known as Peak XV) as 29,002 feet (8,840 m) high, after several years of calculations based on observations made by the Great Trigonometric Survey.
More recently, the mountain has been found to be 8,848 metres (29,029 ft) high, although there is some variation in the measurements. On 9 October 2005, after several months of measurement and calculation, the PRC's State Bureau of Surveying and Mapping officially announced the height of Everest as 8,844.43 m ± 0.21 m (29,017.16 ± 0.69 ft). They claimed it was the most accurate and precise measurement to date. This height is based on the actual highest point of rock and not on the snow and ice covering it. The Chinese team also measured a snow/ice depth of 3.5 m, which is in agreement with a net elevation of 8,848 m. The snow and ice thickness varies over time, making a definitive height of the snow cap impossible to determine.
The elevation of 8,848 m (29,029 ft) was first determined by an Indian survey in 1955, made closer to the mountain, also using theodolites. It was subsequently reaffirmed by a 1975 Chinese measurement. In both cases the snow cap, not the rock head, was measured. In May 1999 an American Everest Expedition, directed by Bradford Washburn, anchored a GPS unit into the highest bedrock. A rock head elevation of 8,850 m (29,035 ft), and a snow/ice elevation 1 m (3 ft) higher, were obtained via this device. Although it has not been officially recognized by Nepal,this figure is widely quoted. Geoid uncertainty casts doubt upon the accuracy claimed by both the 1999 and 2005 surveys.
A detailed photogrammetric map (at a scale of 1:50,000) of the Khumbu region, including the south side of Mount Everest, was made by Erwin Schneider as part of the 1955 International Himalayan Expedition, which also attempted Lhotse. An even more detailed topographic map of the Everest area was made in the late 1980s under the direction of Bradford Washburn, using extensive aerial photography.
It is thought that the plate tectonics of the area are adding to the height and moving the summit northeastwards. Two accounts suggest the rates of change are 4 mm (0.16 in) per year (upwards) and 3-6 mm (0.12-0.25 in) per year (northeastwards), but another account mentions more lateral movement (27 mm/1.1 in), and even shrinkage has been suggested.