Aggregates Manager Digital Magazine
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Bill Langer is a consulting research geologist who spent 41 years with the U.S. Geological Survey before starting his own business. He can be reached at Bill_Langer@hotmail.com CARVED IN STONE 44 AGGREGATES MANAGER / October 2016 Pop quiz! What is the highest place on Earth? A. Mount Chimborazo (Ecuador), B. Mauna Kea (Hawaii), C. Mount Everest (Nepal), or D. All the above. Whenever that question is asked, many people wouldn't even think twice before answering, "Mount Everest." But is it? Let's look at each of the three mountains. A. Mount Chimborazo – The other day, one of my grandkids was sitting on an exercise ball. "Look," I said. "You made an oblate spheroid." I then ex- plained that the Earth is not round; it also is an oblate spheroid. The centrifugal force created by the Earth's rotation causes it to flatten at the poles and bulge at the equator just like the ball. This oblate shape results in points on the Earth's surface that are located along the equator being more distant from the Earth's center (geocenter) than those located at the poles. Based on measurements obtained using high-pre- cision space geodesy, it is estimated that Earth has a polar radius (from the geocenter to the poles) of 3,949.9 miles, whereas its equatorial radius (from the geocenter to the equator) is 3,963.2 miles. Therefore, objects located along the equator are about 13 miles further away from the geocenter than objects locat- ed at the poles. How does this relate to Chimborazo? Well, Chimborazo is only 20,703 feet above sea level whereas the peak of Mount Everest is 29,029 feet above sea level. But, because Chimborazo is located very near the equator (at the highest point of the planet's bulge), it receives an additional boost of about 13 miles. Calculating in that boost, Mount Everest is only 3,965.8 miles from the geocen- ter of the Earth while Chimborazo is 3,967.1 miles. So, the correct answer for highest place on Earth is Chimborazo, which is about 1.3 miles farther from the Earth's geocenter than Mount Everest. B. Mauna Kea Mauna Kea is a dormant volcano located on the island of Hawaii. Its summit is at 13,802 feet. However, Mauna Kea sits on the sea floor, almost 19,685 feet below sea level. Mauna Kea actually measures 33,484 feet tall from the base to the summit. Mount Everest, on the other hand, sits on the Tibetan Plateau, which has an altitude of about 14,800 feet. That means Mount Everest only stands a mere 14,265 feet above its base. So the correct answer for the highest place on Earth, as measured from its base to its peak, is Mauna Kea, not Mount Everest. C. Mount Everest However, the altitude of Mount Everest is 29,029 feet above sea level. No other mountain on Earth has a higher altitude than Mount Everest. So the correct answer to the highest place on Earth, as measured by altitude, is Mount Everest. So there you have it. The correct answer to the pop quiz is D – All the above. And if any of you have climbed Mount Everest, I won't argue… you conquered the highest mountain on Earth. It's all a matter of perspective. You may think you know the answer, but it's all a matter of perspective. The Highest Place on Earth Mount Chimborazo Mauna Kea Mount Everest