How Did They Measure the Height of Mt. Everest?

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iStock

Sibylle Hechtel:

Methods to measure the height of Mount Everest have changed over time, from simple geometry in the past, to GPS more recently. A story in The New York Times, “How Tall Is Mount Everest? For Nepal, It’s a Touchy Question.” discusses the controversy over different results for the height of Everest, and a planned expedition to measure it from the summit.

Estimates of the height of Everest vary. According to The New York Times article:

“Today, Everest’s height is widely recognized as 29,029 feet. But teams from around the world, including China, Denmark, Italy, India and the United States, have come up with other calculations, which have sometimes strayed a little bit higher, or a little bit lower, than that figure. Italy, in 1992, lopped seven feet off the standard height, measuring it at 29,022 feet. In 1999, a measurement by American scientists pushed the peak a little higher, saying the mountain reached 29,035 feet.”

And the height can change. Again, according to The New York Times:

"Roger Bilham, a geologist at the University of Colorado Boulder, said Everest’s location in the zone of compression between southern Tibet and India means it sinks during earthquakes and rises in the period between them. A major earthquake in 1934 lowered the mountain by 63 centimeters, or about two feet, according to data provided by Mr. Bilham.

In the 19th century, the height of Everest was calculated by measuring the angles between the top of the mountain and points on the ground whose positions relative to the average height of the sea were already known.

Now, surveyors place a global positioning system 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.

To prepare for the country’s own expedition, Nepali surveyors will collect measurements this month along the country’s southern plains, where they plan to calculate sea level. A team of Sherpas are also being trained to bring a GPS receiver to the summit. The cost to measure the mountain is estimated at $250,000.”

This post originally appeared on Quora. Click here to view.

Take Advantage of Amazon's Early Black Friday Deals on Tech, Kitchen Appliances, and More

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Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

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Why Doesn’t the U.S. Use the Metric System?

Choose your fighter.
Choose your fighter.
William Warby, Unsplash

After the French Revolution in the late 18th century, the fledgling French republic devised a new unit of measurement called the “meter”—one ten-millionth of the distance between the North Pole and the equator. That became the basis for the metric system, which was eventually adopted in many other countries around the world.

The U.S. wasn’t among them. Though Thomas Jefferson did show interest in the system when he was secretary of state in the 1790s, no change ever came to fruition. According to Northwestern University history professor Ken Alder, Americans may have simply been resistant to the idea of standardizing something on a global scale. “I understand when people resent it as a remote force of globalization that produces uniformity, and it's perfectly rational to want local control,” he told Live Science. “It can also be about taking a position against something that's hyperrational and French.”

Furthermore, Britain’s Industrial Revolution began to take hold in the U.S. during the 1800s, and most manufacturers were calibrating machinery and measuring products using inches, pounds, and all the other familiar units of Britain’s imperial system. As Encyclopaedia Britannica explains, shifting to the metric system would’ve been laborious and costly; whenever Congress brought it up, business owners and citizens quickly shut it down. Two centuries later, those same issues continue to keep the U.S. from committing to the metric system.

That’s not to say we haven’t tried. In 1975, Congress passed the Metric Conversion Act, which encouraged businesses to transition to metric units of measurement. Since it wasn’t mandatory—and imperial units would still be accepted—it hardly upended the status quo. Later that decade, President Jimmy Carter spearheaded a campaign to swap miles for kilometers on road signage, but that didn’t stick, either.

Alder pointed out that France was probably only able to implement a whole new system because the country was in a state of complete upheaval at the time, and many other old processes were changing, too. Britain was also undergoing a large-scale political renovation when it finally switched to the metric system in the 1970s. Because the U.S. government has been relatively static since the formation of the Constitution, we haven’t had a similar opportunity.