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Why isn’t the Earth perfectly round?

The highest point from the center of the Earth is not Mount Everest but the volcano Chimborazo due to the imperfect shape of the blue planet.





The Earth has a slightly flattened shape and bulges at the equator.  Photo: NASA/DSCOVR EPIC

The Earth has a slightly flattened shape and bulges at the equator. Photo: NASA/DSCOVR EPIC

If there were a giant tape measure measured from the center of the Earth, the highest point on the planet would not be the summit of Mount Everest but the Chimborazo volcano in Ecuador, a country located at the equator. Chimborazo wins in this case because the Earth is slightly flattened at the poles, in the same way that a person presses both hands to the top and bottom of a ball. This causes the equator to swell. Therefore, instead of being perfectly spherical, the Earth is an oblate sphere.

“In fact, most planets and moons are not truly spherical. They are often distorted in some way,” said James Tuttle Keane, a planetary scientist at NASA’s Jet Propulsion Laboratory . The cause, he said, is the centrifugal force, or outward force present in a rotating body.

The rotating planet will be affected by centrifugal force. If a person rotates on their own while sitting in a chair or standing on their feet, the person will also feel pulled away from the center point and the arms or legs swing out. “When you’re sitting on the Ferris wheel, there’s a little extra force applied to you on that swing, causing you to feel pulled to the side,” says Keane.

The planets and moons rotate on their own, so centrifugal force causes them to bulge at the equator. This effect is likely to be very small. In the solar system, Jupiter and Saturn are two relatively conspicuous examples. If you look at the panoramic images of these gas giants, you will see that they are slightly flattened and the middle is bulging. Their flattened shape is easier to see because these are the fastest rotating planets in the solar system, Keane said. The faster the object rotates, the greater the centrifugal force acting on it.





Dwarf planet Haumea is shaped like an egg.  Photo: Instituto de Astrofisica de Andalucía/NASA

Dwarf planet Haumea is shaped like an egg. Photo: Instituto de Astrofisica de Andalucía/NASA

An example of the extreme effects of centrifugal force is the dwarf planet Haumea. This dwarf planet is located in the Kuiper Belt, a region of space composed of icy objects beyond the orbit of Neptune. Haumea is about as large as Pluto but rotates very quickly, completing one revolution in just four hours. It spins so fast that it turns into an almost egg-shaped shape.

Thu Thao (According to Live Science)

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