The world’s tallest mountain may have shrunk following the 2015 Nepal earthquake. That’s what a group of Indian scientists want to check, after satellite data suggested Everest may have reduced in height following the impact. “Everest was last measured in 1955 by the Indian government,” said the country’s Surveyor-General Swarna Subba Rao. That survey recorded the height of the world’s tallest mountain as 8,848 meters, or 29,029 feet. Rao wants to send a team of about 30 scientists and surveyors to measure the mountain, which may have dropped by at least a meter following the 7.8 magnitude Nepal quake. Getting permission “The actual measurement only takes a few days, but the preparation can take anywhere up to six months, since we have to monitor the weather and get clearance,” Rao said. Everest’s summit sits at the border of Tibet and Nepal, and Beijing and Kathmandu must be consulted in order to carry out such an expedition. “To remeasure the height of Everest is a matter of pride for any country or a scientific community,” said Suresh Man Shrestha, deputy director general of Nepal’s Survey Department. “That is their chance to showcase their talents and resources. So it is obvious many countries want to get involved in anything Everest-related.” A Chinese team measured the mountain in 2005, Shrestha said, but since the research was not authorized by Nepal, the country did not recognize the data as the official height. The Chinese team measured the height at 8,844 meters (29,015 feet). “Nepal’s survey department is working on a plan to survey Everest’s height on our own – since there have been many claims about movement of its tectonic plate during the recent earthquake,” Shrestha said. He added that Indian scientists may be able to join that survey but will have to apply through formal channels. Rao said his team has had informal discussions with Nepalese officials and are in the process of making a diplomatic request. How do you measure a mountain? The Indian team plans to use a combination of precise GPS measurements and triangulation to measure the height of the mountain, at an estimated cost of around $800,000. GPS technology similar to that found in most smartphones can give latitude, longitude and height measurements, provided weather conditions do not prevent a clear satellite signal. “A signal receiver would be installed at the base camp – at a nearest point possible to the summit of Everest,” Shrestha explained. “The area has to be even and stable. Ideally it should be installed at the top of Everest but due to excess snowfall, crazy wind, and uneven surface, it is not possible.” The team will monitor signals sent between the receiver and satellites for 5-6 weeks, and convert the time it takes the signals to arrive into a height measurement. Though Shrestha said the Nepalese team will not use traditional methods to measure the mountain, as GPS is more accurate, Rao said the Indian scientists also hope to use triangulation to get a height measurement. This ancient trigonometric method measures the angles in a triangle formed by three survey control points. Provided the length of one side of the triangle is known, the other distances can be easily calculated.