“Rope pulling” between Earth, Moon and Sun can cause tectonic plates to move

The tectonic plates that make up the Earth’s solid crust are always moving, affecting life on our planet in different ways.

These huge plates may move slowly, but they create many of the Earth’s unique topographic features, such as mountains, abysses, individual islands, archipelagos, and ocean trenches — all on a continental scale.
Gravitational interactions between the Earth, the Moon and the Sun could cause tectonic plates to move, scientists say

Earthquakes, volcanoes, and tsunamis, however, are also the result of the constant flow of the lithosphere — the rocky crust and the upper crust.

The average tectonic plate can move about 40 mm per year – about the same speed as a nail grows – while the fastest, the Naska plate in western South America, moves about 160 mm per year, about the same speed as hair grows.

The dominant consensus on what drives plate motion has long been established on convection currents within the Earth’s crust, theorizing that the movement of massive amounts of heat draws the plates around from below.

But a new study by scientists at the University of Washington in St. Louis suggests that there is not enough energy inside the Earth needed to move tectonic plates, and instead unbalanced gravitational forces between the Earth, Moon and Sun together stimulate the circulation of the entire “mantle”. “.

The variety of plate movements comes from changes in the magnitude and direction of unbalanced gravitational forces over time.

Researchers have suggested that the Earth’s plates may be moving because the Sun is gravitating toward the Moon, causing the Moon to orbit the Earth to lengthen.

Over time, the position of the “baricenter,” or center of mass between the bodies orbiting the Earth and the Moon, has moved closer to the Earth’s surface. It now oscillates 600 kilometers a month relative to the geocenter (center of the Earth), scientists say. This creates internal stresses as the Earth continues to spin.

“Because the oscillating baricent is about 4,600 kilometers from the geocenter, the tangential orbital acceleration of the Earth and solar traction are unbalanced except at the baricenter,” said Professor Anne Hoffmeister, who led the study.

“The warm, thick and strong inner layers of the planet can withstand these stresses, but its thin, cold, brittle lithosphere responds by breaking.”

Furthermore, the authors claim that the daily rotation of the Earth, which flattens the planet from a perfect spherical shape, contributes to this fragile defect in the lithosphere.

These two independent stresses create a mosaic of tiles observed in the outer shell, the authors suggest.

The variety of plate movements comes from changes in the magnitude and direction of unbalanced gravitational forces over time.

It is difficult for researchers to test this theory. They suggested that a closer look at Pluto’s crust could provide additional information on how tectonic plates respond to gravitational forces.

“One test would be a detailed examination of Pluto’s tectonics, which is too small and too cold for convection but has a giant moon and a surprisingly young surface,” said Professor Hoffmeister.

The study also includes a comparison of rocky planets that show that the presence and longevity of volcanism and tectonics depend on the specific combination of the size of the moon, the moon’s orbital orientation, proximity to the sun, and the rate at which the body rotates and cools.

“Earth is the only rocky planet with all the factors needed for plate tectonics,” said Professor Hoffmeister.

“Our uniquely large moon and especially the distance from the sun are essential,” she added.

The study was published by the Geological Society of America. (Independent)

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