GEOGRAPHY

Mount Everest is the tallest mountain in the world, but precisely how tall is it? The question is not so simple. (New York Times)

Use this gorgeous map to zoom in on the 29,035ish-foot peak.

Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.

Discussion Ideas

• How tall is Mount Everest? The New York Times says “it’s not such a simple question.” Why not? What questions complicate measurement? What do your students think?
  • Should a summit’s snowcap be included in assessing a mountain’s elevation, or should surveyors drill down to the mountain’s rock base?
    • If snowpack is included, during what time should surveyors measure?
    • Snow on Mount Everest can vary significantly depending on the season (there’s more snow in winter) and wind velocity (those jet streams can strip meters of icy snow off the mountaintop).
  • How often should surveys be taken?
    • In the seismically active region of the Himalaya, mountains sink during earthquakes and rise in the periods in between.
      • “A major earthquake in 1934 lowered [Mount Everest] by 63 centimeters, or about two feet,” according to one expert.
  • From what base should a mountain be measured?
    • sea level? This is the most common measurement for determining elevation.
    • the center of the Earth? The Earth is not a perfect circle. It is an oblate spheroid, meaning it bulges slightly around the center. This measurement would put mountains in the equatorial zone at a higher elevation than those at the poles.
    • the surrounding region? “Prominence” measures elevation by the vertical distance between a summit and the lowest contour line encircling it and no higher summit. Mountains that are part of high-elevation ranges such as the Himalaya and Andes thus have lower prominence, as they are flanked by other high summits.
  • Who is measuring?
    • Most surveyors put Mount Everest’s elevation at 8,850 meters (29,029) feet.
    • A U.S. survey recognized by National Geographic puts the mountain’s elevation at 29,035 feet. (That’s what you’ll see on our maps!)
    • An Italian team found the elevation to be 29,022 feet.
    • A Chinese team determined the elevation to be 29,017 feet, but has since rescinded that measurement. (More on that later.)

• Mount Everest is generally regarded as our tallest mountain. Would changing any factors listed above alter that interpretation? Check out slides one and 18 in this fun GeoStory for some help, or wonder “What’s up, Mount Everest” with our fast facts.
  • Changing how we define “tallest” would definitely change our identification of the “tallest mountain.”
    • From sea level, Mount Everest is the tallest mountain on Earth.
    • From the seafloor, Hawaii’s Mauna Kea towers 9,966 meters (32,696 feet)—much higher than Everest.
    • From the center of the Earth, Chimborazo, Ecuador, is 6,384 kilometers (3,967 miles) from the Earth’s center, while Everest is about two kilometers less. (The summit of Chimborazo is only about one degree south of the Equator, where the Earth’s “bulge” is thickest.)
    • One of the most topographically prominent summits is Denali, Alaska, whose “parent” summit is Aconagua, thousands of kilometers away in the Andes of South America.
  • Out-of-this-World: Everest, Mauna Kea, Chimborazo, and Denali are among the highest elevations on Earth. However, they are all dwarfed by Olympus Mons, the extinct Martian volcano that stands as the tallest mountain in the solar system. Olympus Mons is about the same width as the state of Arizona and, at 25 kilometers (16 miles) high, more than two-and-a-half times the elevation of Mount Everest. Learn more about Olympus Mons (point 11) and other features of the Martian landscape here.

• Why are Nepali surveyors measuring Mount Everest?
  • Although Mount Everest is a geographic feature shared by China and Nepal, Nepali engineers or scientists have never been involved in a survey of the mountain.
    • “Mount Everest is our treasure,” said Buddhi Narayan Shrestha, the former director general of Nepal’s Department of Survey. “What will happen if foreign experts continue to reduce the height of our mountain without us participating?”
  • Having the tallest mountain in the world is an economic asset.
    • Tourism to the Chinese side of Mount Everest dropped after Chinese surveyors reduced the elevation by about 10 feet. China has since recalculated and accepted the higher estimate.

• How are Nepali surveyors measuring the mountain?
  • First, Nepali surveyors will collect measurements along the country’s southern plains, where they plan to calculate sea level.
  • Second, surveyors will place a global positioning system (GPS) receiver on the summit ice for an hour, and mathematically calculate the height of the sea from satellites and measurements of gravity at the base. Stay tuned.

TEACHERS TOOLKIT

New York Times: How Tall Is Mount Everest? For Nepal, It’s a Touchy Question.

Earth 3D Map: Mount Everest 3D Maps

Nat Geo: What’s Up, Mount Everest?

Nat Geo: Earth’s Extremes