NASA scientists identify three causes of drift in the axis of rotation of the Earth

Scientists have known for a long time that the Earth revolves around the Sun. When Earth ends orbiting the sun or the star in the center of our solar system, it gives us a year. Our planet that turns on its axis, an imaginary straight line that crosses the North and South poles, gives us the length of a day (24 hours).

Although the rotation of the Earth seems stable, it is far from perfect. The earth drifts and wobbles when it rotates on its axis of rotation. This movement is known as polar movement and evidence suggests that the axis of rotation drifts about 4 inches (10 centimeters) a year in the 20th century. During a century, it is more than 10 meters.

Using observational data and model data from the twentieth century, researchers identified for the first time three processes responsible for this drift. These are the loss of ice in Greenland, the glacial bounce and the convection of the mantle.

"The traditional explanation is that a process, the glacial rebound, is responsible for this movement of the axis of rotation of the Earth. But recently, many researchers have assumed that other processes could have significant effects on it too, "said Surendra Adhikari, head of NASA's propulsion laboratory in Pasadena. We have collected models for a subsequent motion of the axis of rotation. We have identified not one but three sets of processes that are essential – and the melting of the global cryosphere (especially Greenland) during the twentieth century is one of them. "

As the Earth warmed in the 20th century, the loss of ice in Greenland has increased at an alarming rate. According to the latest study, a total of about 7,500 gigatonnes – the weight of more than 20 million Empire State Buildings – from Greenland ice fell into the ocean during this period. When a large amount of mass was transferred to the oceans, it caused a drift of the axis of rotation of the Earth.

The study also reveals that the rebound of glaciers or the melting of heavy glaciers at the end of the last ice age is responsible for only about a third of the polar drift in the twentieth century. The third and final key factor is mantle convection or the movement of tectonic plates on the surface of the Earth. It is triggered by the heat of the Earth's core.