Highest Mountain in the World

Highest Altitude: An altitude of 8,848.86 meters (29,031.69 feet) above sea level makes Mount Everest the mountain on Earth with the highest altitude. "Highest altitude" means that it has the highest elevation above mean sea level.

Everest from Gokyo Ri: A clear-sky view of the Mount Everest summit through a telephoto lens from the summit of Gokyo Ri. Image copyright iStockphoto / Grazyna Niedzieska.

Each year hundreds of people attempt to climb Everest. About 5000 people have been successful - some multiple times. However, about 300 people have died climbing Everest - that is a mortality rate of about 6%!

Mount Everest: Highest Altitude

If you ask almost anyone to name the highest mountain in the world, their answer will probably be "Mount Everest." Mount Everest, located on the border between China and Nepal, has an altitude of 8,848.86 meters (29,031.69 feet) - making it the highest mountain in the world. The altitude of 8,848.86 meters is officially recognized by China and Nepal. Both countries agreed to use the elevation of the mountain's snow cap, rather than a bedrock elevation of 8,844 meters.

What does "world's highest" really mean?

Mount Everest is called the world's highest mountain because it has the "highest elevation above sea level." We could also say that it has the "highest altitude."

The peak of Mount Everest is 8,848.86 meters (29,031.69 feet) above sea level. No other mountain on Earth has a higher altitude. However, some mountains might be considered "taller" (with taller being "the total vertical distance between their base and their summit").

Tallest Mountain: The base of Mauna Kea is about 6000 meters below sea level, and the summit is about 4000 meters above sea level. The distance between the foot of the mountain and the summit is about 10,000 meters. This makes Mauna Kea the "tallest" mountain in the world.

Snow in Hawaii? Satellite view of the island of Hawaii. The two snow caps are Mauna Loa (center) and Mauna Kea (to the north). Image by NASA.

Mauna Kea: Tallest Mountain

Mauna Kea, a volcanic mountain on the island of Hawaii, has an altitude of 4,207 meters (13,803 feet) - much lower than Mount Everest. However, Mauna Kea is an island, and if the distance from the bottom of the nearby Pacific Ocean floor to the peak of the island is measured, then Mauna Kea is "taller" than Mount Everest.

Mauna Kea is over 10,000 meters tall compared to 8,848.86 meters for Mount Everest - making it the "world's tallest mountain."

Astronomical Observatories on Mauna Kea: The summit of Mauna Kea holds other distinctions. In addition to being the summit of the world's "tallest" mountain, it is also the home of the world's largest astronomical observatory. At an elevation of nearly 14,000 feet above sea level, the observatory is above 40% of Earth's atmosphere. The atmosphere above the mountain is extremely dry and almost cloud-free. This makes it an ideal location for an observatory. And, yes, that is snow on the ground in Hawaii - the altitude is high enough and cold enough to accumulate snow. Photo copyright iStockphoto / GeorgeBurba.

Highest Above Earth's Center: The Earth does not have the shape of a perfect sphere. Instead, its diameter is greatest near the equator. In the diagram above, the gray dashed line is a perfect circle, and the solid blue line represents the shape of the Earth (exaggerated a bit to make its departure from spherical obvious). Chimborazo is located near the equator where Earth's diameter is greatest. This makes the summit of Chimborazo the highest point above the center of the Earth.

Snow at the Equator? Photo of Chimborazo mountain, Ecuador. Even though the mountain is very close to the equator, it is high enough to support a year-round snow cap. Image copyright iStockphoto / ache1978.

Chimborazo: Farthest from the Center of the Earth

Chimborazo, a volcano in Ecuador, has an altitude of 6,263 meters (20,549 feet). Mount Everest has a higher altitude, and Mauna Kea is "taller." However, the top of Chimborazo is farther from the center of the Earth than the top of Mount Everest and the top of Mauna Kea.

Farther from the center of the Earth?

Earth's shape is not a perfect sphere. Instead, it is an oblate spheroid - meaning that it is a few miles wider at its equator than locations north and south of the equator. In addition, Earth's shape is also a slightly pear-shaped oblate spheroid - meaning that it is a few miles wider below the equator than above the equator.

That shape makes it possible for the top of Chimborazo, which is located slightly south of the equator (and shorter than Mount Everest) to be farther from the center of the Earth than the top of Mount Everest (which is a considerable distance north of the equator).

Chimborazo is located about one degree south of the equator. At that location, it is 6,384 kilometers (3,967 miles) above Earth's center, or about 2 kilometers (about 1.2 miles) farther from Earth's center than Mount Everest.