- There are two huge dense rocks hundreds of miles high deep inside the earth.
- The latest research shows that these spots are remnants of planets that struck the Earth 4.5 billion years ago.
- The collision of the earth with this ancient planet called Theia may help create the moon.
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If you want to stare into the depths of the earth’s crust, you will find two huge masses of rocks holding the core of the planet like two hands.
The origin of these mysterious, continental-sized rock formations (one under the Pacific Ocean and the other under Africa) puzzled geologists for forty years. Some experts believe that massive rocks are fragments of tectonic plates, trapped under their corresponding rocks.
But according to new research, their origin may be otherworldly.
A team of scientists at Arizona State University believes that these spots are the remnants of a “Martian-sized embryo”
Qian Yuan, the principal researcher behind the findings, studies geodynamics at Arizona State University in the United States. He said that after the ancient collision, some parts of Theia may have sunk and been preserved deep in the mantle of our planet-the semi-solid layer between the crust and the core.
Yuan told insiders that these works are “hundreds of times larger than Mount Everest in volume.”
Dense area with a height of up to 621 miles
Geologists discovered these blocks by propagating seismic waves down to the earth (their technical name is Large Low Shear Velocity Province). In Africa and the Pacific Ocean, the speed of these seismic waves slows down the crawling speed, which indicates that the density of the rock is greater than that of its surroundings. The animation below shows the size of these areas based on 2016 analysis.
According to Yuan, the density of these spots is 1.5% to 3.5% higher than the density of the rest of the earth, and the temperature is higher.
Yuan’s model shows that if Theia is iron-rich and highly dense, any debris that breaks when it hits the earth will sink deep into our earth’s mantle. There, they could have accumulated undisturbed, instead of mixing into the rest of the mantle.
Yuan said that the denser crust of the earth may also sink into the mantle and join together, thus promoting the growth of the land mass over time.
Figuring out the composition of these plates is challenging. Their deepest part is 1,800 miles below our feet, the part of the mantle closest to the outer core of the earth. Their height is 621 miles (1,000 kilometers), which is two to three times higher than the altitude.
But scientists have discovered that plumes of hot rocks and magma from some volcanoes in Iceland and Samoa come from these spots. By analyzing the composition of magma, researchers can gain insights into the composition of these mysterious buried blocks. According to a 2019 study, certain elements in the volcanic plume can be traced back to about 4.5 billion years ago-Theia is said to have attacked the earth.
When planets collide
The idea that the collision between the asteroid and the Earth would help form the moon has been around for more than 45 years. But one problem with this hypothesis is that scientists have yet to find any evidence of Thea’s existence.
A 2016 study showed that this is because the earth and the core of Tia are fused together. Yuan said another idea that came up in 2018 was that when planets collided, they were all “almost completely vaporized.” According to this idea, the earth became a rapidly rotating mass of molten and vaporized rock, called a serous membrane, and then collapsed back into the molten planet. Part of the rotating matter became the moon, and Theia was no longer.
The third theory (called “go and go” according to Yuan) is that Tai Ya just glanced at the earth, a large piece of a planet or the combination of two fragments to form the moon. However, the composition of the moon is almost exactly the same as the composition of the earth, which shows that it contains very little Sia.
Yuan’s new discoveries will be published soon in “Geophysical Research Letters”, which may finally prove that Theia existed in the solar system billions of years ago.