Mount Everest or Chomolungma is the highest point on Earth, as measured by the height of its summit above sea level. The mountain, which is part of the Himalaya range in High Asia, is located on the border between Nepal and China.
Measurement
Radhanath Sikdar, an Indian mathematician and surveyor from Bengal, was the first to identify Everest as the world's highest peak in 1852, using trigonometric calculations based on measurements of "Peak XV" (as it was then known) made with theodolites from 240 km (150 miles) away in India. Measurement could not be made from closer due to a lack of access to Nepal. "Peak XV" was found to be exactly 29,000 feet (8,839 m) high, but was publicly declared to be 29,002 feet (8,840 m). The arbitrary addition of 2 feet (0.6 m) was to avoid the impression that an exact height of 29,000 feet was nothing more than a rounded estimate.
The mountain was recently found to be 8,848 m (29,028 feet) high, although there is some variation in the measurements. The mountain K2 comes in second at 8,611 m (28,251 feet) high. On May 22, 2005, the People's Republic of China's Everest Expedition Team ascended to the top of the mountain. After several months' complicated measurement and calculation, on October 9, 2005, 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 measurement to date.[1]. But this new height is based on the actual highest point of rock and not on the snow and ice that sits on top of that rock on the summit, so, in keeping with the practice used on Mont Blanc and Khan Tangiri Shyngy, it is not shown here. The Chinese also measured a snow/ice depth of 3.5 m,[4] which implies agreement with a net elevation of 8,848 m. But in reality the snow and ice thickness varies, making a definitive height of the snow cap, and hence the precise height attained by summiteers without sophisticated GPS, impossible to determine.
The elevation of 8,848 m (29,028 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 [2]. 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 feet), and a snow/ice elevation 1 m (3 ft) higher, were obtained via this device [3]. Nepal, however, did not officially recognize this survey, and the discrepancy with the above mentioned 2005 Chinese survey is significantly greater than the surveys' claimed accuracy.
It is thought that the plate tectonics of the area are adding to the height and moving the summit north-eastwards. Two accounts, [4], [5] suggest the rates of change are 4 mm per year (upwards) 3-6 mm per year (northeastwards), but this account[6] mentions more lateral movement (27 mm), and even shrinkage has been suggested [7].
Everest is the mountain whose summit attains the greatest distance above sea level. Two other mountains are sometimes claimed as alternative "tallest mountains on Earth". Mauna Kea in Hawaii is tallest when measured from its base; it rises over 10,203 m (about 6.3 mi) when measured from its base on the mid-ocean floor, but only attains 4,205 m (13,796 ft) above sea level. The summit of Chimborazo in Ecuador is 2,168 m (7,113 ft) farther from the Earth's centre (6,384.4 km or 3,967.1 mi) than that of Everest (6,382.3 km or 3,965.8 mi), because the Earth bulges at the Equator. However, Chimborazo attains a height of 6,267 m (20,561 ft) above sea level, and by this criterion it is not even the highest peak of the Andes.
The deepest spot in the ocean is deeper than Everest is high: the Challenger Deep, located in the Mariana Trench, is so deep that if Everest were to be placed into it there would be more than 2 km (1.25 mi) of water covering it.
The Mount Everest region, and the Himalayas in general, are thought to be suffering ice-melt due to global warming.[citation needed] The exceptionally heavy Southwest summer monsoon of 2005 is consistent with continued warming and augmented convective uplift on the Tibetan plateau to the north.[citation needed]
You could get more information from the link below...
2006-11-29 00:28:23
·
answer #4
·
answered by catzpaw 6
·
0⤊
1⤋