Earth is not a perfect sphere but you shouldn’t care about those who claim that the Earth is flat because it is not. So, the Earth is not circular as seen in the photos but slightly bulgy around the equator and it possesses a wobbling motion also known as ‘polar motion’ when revolving around its own axis and around the sun. But there’s more to the story as added by the latest research paper published by NASA’s Jet Propulsion Laboratory based in California.
According to the research paper, there are basically three factors that are influencing the Earth’s spin or wobbling motion, also known as polar motion. At first, only one of the major influences was recorded that is glacial rebound, however, the recent paper has suggested that there are at least two more reasons why Earth has gone off-axis by almost 10 meters in a century alone.
Per the paper reads, glacial rebound is a phenomenon when heavy glaciers are formed and cover a large surface of land on Earth such as during the last ice age about 21,000 years ago when major parts of the Earth were covered in thick and dense ice when compresses the Earth a bit cause a slight bulge. However, as the ice melts, it slowly lifts the pressure and the surface tends to rebound slowly which is called glacial rebound. When the ice melts and the pressure it compressed the land with subsidies, the surface rises up a bit causing a difference in Earth’s polar motion.
But that’s just the one-third of the story. Another major factor that influenced Earth’s improper wobbling motion is the ‘mantle convection’. The crust on which we stand is placed on tectonic plates with liquid rocks underneath that tends to move around very ‘slowly’ but it does and thus, impacts the wobbling effect on Earth over time.
Thirdly, humans have been accounted for at least one-third responsible for Earth’s wobbling effect. To elaborate on it, the paper initiated the instance of Greenland which lost an enormous 7,500 gigatons of ice in just the 20th century. Now, the melted ice deposits somewhere else when shifts the weight to another part of the world causing an impact of the Earth’s wobbling effect.
Greenhouse gases and global warming are being associated with a difference in the polar motion and humans are only accelerating the curse without caring much for the environment. Researchers have associated the loss of ice in Greenland as the indicator to the change in polar motion.