After six months' analysis of data, collected by sensors positioned on the summit of the world's highest mountain that were pointed at orbiting satellites, scientists have announced that it is officially 29,035ft (8,850 metres) high, rather than the figure accepted for the past 45 years, 29,028ft (8,848 metres).
The previous summit measurement, made in 1954, was produced by averaging altitude measurements taken from a dozen different observation points around the mountain. For decades it was thought that to get to a height of 29,030ft, while staying on Earth, you would need to take a chair to the top of the mountain, and stand on it. The latest version is accurate to a few centimetres.
It also shows that Mount Everest is moving steadily north-east at a rate of 2.4 inches (6cm) a year, because of the geological fault system that is slowly pushing India under Nepal and China, creating the Himalayas.
Bradford Washburn, director of the Millennium Expedition to Mount Everest in May, which did the project, said: "At this moment, six months after the measurements were taken, Mount Everest may already be a trifle higher, as well as slightly northeast of the position that it occupied early in May." He presented the new measurements earlier this week at the National Geographic Society in Washington.
The data was collected by two American and five Sherpa climbers who spent nearly two hours on the mountain's summit on 5 May, with half the time spent collecting data from orbiting Global Positioning System (GPS) satellites, which use atomic clocks to produce a precise system for location anywhere on the Earth. GPS is used by all sorts of navigation systems in aircraft, vehicles and ocean-going craft.
Bill Crouse, one of the climbers, said that the group "felt like monkeys in space". Their tasks consisted mainly of pressing buttons to download data from the GPS satellites, with no knowledge of what it might mean.
National Geographic said it will revise all its new maps and globes with the new elevation. Allen Carroll, the society's chief cartographer, said: "It is clearly the most authoritative and thoroughly executed measurement of the highest point on the Earth's surface."
Mr Crouse said he was excited about the news, now that the number-crunching had been done. "It's a big deal when you change the height of the highest peak in the world."Reuse content