This New Paper Suggests That Earth’s Tectonic Activity Has An Unseen Source

Earth’s outer layer has more than 20 tectonic plates and as these massive slates glide about the face of the planet, we get the movement of continents, and interaction at the boundaries, not least of which is the rise and fall of entire mountain ranges and oceanic trenches.

The source of these movements is still not known for sure. some believe that it is the convection currents generated by the planet’s hot core but it’s doubtful if they can generate enough energy for this to happen.

In a new study, authors have suggested that the interplay of gravitational forces from the Sun, Moon, and Earth could be responsible for the movement of Earth’s tectonic plates.

Key to the hypothesis is the barycenter – the center of mass of an orbiting system of bodies, in this case, that of Earth and the Moon. This is the point around which our Moon orbits, and it’s not directly in the center of mass of our planet, which we call the geocenter.

The barycenter within Earth changes over the course of the month by as much as 600 kilometers (373 miles) because the Moon’s orbit around Earth is elliptical due to our Sun’s gravitational pull.

“Because the oscillating barycenter lies around 4,600 kilometers [2,858 miles] from the geocenter, Earth’s tangential orbital acceleration and solar pull are imbalanced except at the barycenter,” says geophysicist Anne Hofmeister, from Washington University in St. Louis.

“The planet’s warm, thick and strong interior layers can withstand these stresses, but its thin, cold, brittle lithosphere responds by fracturing.”

“Differences in the alignment and magnitude of the centrifugal force accompanying the solar pull as Earth undulates in its complex orbit about the Sun superimpose highly asymmetric, temporally variable forces on Earth, which is already stressed by spin,” the researchers write.

Wild New Paper Suggests Earth's Tectonic Activity Has an Unseen Source -  Jai Tuss

“Our uniquely large Moon and particular distance from the Sun are essential,” says Hofmeister.

As the Sun’s gravitational pull on the Moon is 2.2 times greater than Earth’s pull, it will get drawn away from our planet over the next billion years or so.

That said, the gravitational forces at play still need Earth’s hot interior for all this to work, the researchers argue.

“We propose that plate tectonics result from two different, but interacting gravitational processes,” they write. “We emphasize that Earth’s interior heat is essential to creating the thermal and physical boundary layer known as the lithosphere, its basal melt, and the underlying low-velocity zone.”

The research has been published in GSA Special Papers.

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