The New Height of Mount Qomolangma
The height of Mount Qomolangma is one of the most fascinating questions in geography. Every time its measurement makes a splash across the world. On December 8th, 2020, China and Nepal agreed on a new official height for Mount Qomolangma, ending a long-running dispute over the exact height of the world’s tallest mountain.
The mountain is officially 8,848.86 meters, according to the number agreed upon by both countries. That’s 86 centimeters higher than the measurement made by the Survey of India in 1954, which has been the widely accepted number ever since. Since then, there have been a bunch of other surveys which found slightly different measurements.
So how to measure a mountain?
The main technique that's been used for hundreds of years is trigonometry, to be precise. Surveyors measure two points on the ground and from each point they measure the angle between them and the top of the mountain to give them a triangle. Using those triangles and the laws of trigonometry, they can calculate the height of the mountain.
The first person to measure Mount Qomolangma using that method was George Everest back in 1856. To get the angles, he had to use theodolites, which weighed about 500 kilos. As a result, the Great Trigonometric Survey of British India has pegged the mountain, known to them as Peak XV and later named after Sir George Everest, at 29,002 feet.
Fast forward to the 1950s, and surveyors got a bit of help from photogrammetry, detailed photos taken from the air that they could use to measure heights and distances.
Now people have even fancier technology to measure mountains -- the Global Positioning System or GPS. Surveyors can bring a GPS receiver to the top of the mountain, where satellites in space can pick up their location and work out the height, again, using triangles.
The 1954 measurement included the mountain’s snow-cap, but China came up with a shorter measurement in 2005, when it excluded the cap. In 2020, China and Nepal finally agreed to re-measure the mountain from the top to the mean sea level, using GPS and the latest surveying equipment. They spent two years training a team for the project, then placed several markers around the mountain and another at the very top to come up with the new number.
There's debate over whether you should count the snow on top, or just the rock underneath. And there's a possibility that the height has actually changed because of erosion and earthquakes. In fact, scientists reckon this earthquake in Nepal in 2015 might have knocked some height off this very high mountain.
With no climbers around due to the pandemic, scientists regarded it the perfect time for a re-measure. The team of surveyors that worked out the new height of the mountain is the first and the only group to summit Qomolangma in 2020. Let’s remember the height of the world’s highest mountain – 8848.86 meters.
1. make a splash 引起轰动
2. trigonometry n. 三角学
3. theodolite n. 经纬仪
4. peg v. 使尺度、价格等固定于某水平
5. photogrammetry n. 照相测量法