How Do Scientists Determine the World’s Tallest Mountain?

This is a task that seems both simple and complex. After all, we measure things by, well, by measuring them!! We take something that indicates length or distance and go along the entire surface until we can say, “It’s this long, or this high.”

But mountains are a bit more difficult to measure. In fact, the different methods of measurement have led to some controversy about which mountain on the Earth is really the tallest. Different scientists have come up with techniques to make these measurements. The methods are so different that they even come up with unique results.

By the Sea?

Most people assume that we measure the height of things on the surface of the planet in relation to sea level. This method is accepted most widely in the scientific community. Mount Everest tops the list when we measure from sea level – 29,034 feet or 8,850 meters above sea level.

One of the reasons this mountain is considered highest is because it sits on a plateau, far above the plains below. This adds to the overall height of Everest. But scientists have found that Mount McKinley actually has a larger vertical rise from the flat surface on which it appears (5,500 meters compared to 3,700 for Mount Everest). Then there is Mauna Kea. If this mountain is measured from the base under the ocean it is 33,476 feet high.

That gives us an idea of the general method of determining the height of mountains. The numbers depend on where you start measuring from – sea level, the ocean floor or the actual surrounding flat land. But what tools are used to make the measurements?

Technology

In the 21st century and for several years before this mountain height has been measured with such technology as the global positioning system and similar electronic technology. In basic terms, scientists use radio signals sent to satellites from various points to determine the difference in distance. In this method, scientists measure the time it takes signals to travel to and from the satellite.

If you are using a measurement from sea level, you have to know what that level is. The surface of the ocean isn’t at the same level at all places on the planet, but it is within about 300 feet. This means scientists use estimates of where the sea level would be if it actually came right to the base of the mountain.

Before the satellite/GPS technology that allows measurements within a centimeter, (fraction of an inch) scientists and map-makers used trigonometry and land-survey instruments to make the measurements. This involves measuring angles and calculating vertical height. The change to new technology added height to some of the world’s tallest mountains.

So, that’s basically how scientists determine which mountains are the tallest in the world. They have the technology to make very accurate measurements but there is still some difference of opinion on where we should start measuring from. In any case, there are some very tall mountains on planet Earth.