Jakarta, CNN Indonesia —
United States Aeronautics and Space Administration (NASA) state Earth not shaped like a perfect ball. When rotating on its axis, the Earth can float and sway.
The movement of the Earth is known as the polar motion. In the last century the Earth’s axis is said to have shifted approximately 10 meters.
A study published in the journal Earth and Planetary Science Letters in 2018 said the wobble was caused by three factors: ice melting in Greenland, land area expansion due to melting ice, and changes in Earth’s rockiest layer (Earth’s mantle).
The melting ice factor is an effect that is strongly influenced by humans. Rising temperatures during the 20th century have caused the ice to melt in Greenland.
NASA estimates that 7,500 gigatons of Greenland ice melted into the ocean in the 20th century.
Researchers believe melting ice, particularly in Greenland, accounts for about 33 percent of the wobble effect. When the polar ice caps melt, water flows into the oceans and spreads across the globe, causing the destabilization of the planet’s rotation.
“There’s a geometric effect that if you have a mass that’s 45 degrees from the North Pole [Greenland] or the South Pole, it will have a greater impact on shifting the Earth’s rotating axis than the mass right near the pole,” said Eric Ivins, an author from the Jet Propulsion Laboratory, as quoted by NASA on September 19, 2018.
Another factor uncovered by the researchers was glacial rebound, a condition in which land masses that were once under pressure from the heavy weight of the ice began to emerge.
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NASA Reveals Three Factors Shifting Earth’s Axis
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