The remnants of a Teia planet that struck the young Earth 4.5 billion years ago and formed the moon may still be lurking deep in Earth’s mantle.
Deep in the Earth’s mantle, there are two mysterious “spots” that have puzzled earth scientists for a long time. They are called the Large Low Shear Velocity Province (LLSVP). One is located under the African continent and the other is located in the Pacific Ocean. The lower part accounts for about 4% of the mantle. When seismic waves pass through these two places, the velocity becomes slower than passing through other areas of the mantle, showing that there are differences in temperature and composition between the two sides.
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In recent years, scientists have begun to suspect that these two “anomalous” areas are related to the remnants of the ancient dwarf planet Theia, which impacted the early Earth and formed the moon. Because the moon has only about 2% of the Earth’s mass, and the remaining Theia planet has lost mass. unknown.
▲ The large low-shear wave velocity group located in the Earth’s mantle may be the remains of ancient dwarf planets absorbed by the Earth. (Source:Edward Garnero/Caltech）
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According to the Big Collision theory, about 4.533 billion years ago, the planet Teia deviated from its original orbit and collided with the early Earth, melting together to form the present Earth, and part of its mantle and broken crust was ejected into a stable orbit around the Earth. Finally, it re-accreted to form the Moon.
A team composed of scientists from Arizona State University and the California Institute of Technology tried to simulate the original impact, the impact of Teia on the Earth’s mantle, and how the impact remnants circulated in the Earth’s mantle over the next 4.5 billion years. They found that this planet is similar to Mars Most of the energy of a dwarf planet of similar size is still retained in the upper mantle, and the lower mantle has not been completely melted by the impact, so the iron-rich material clumps from the sub-planet remain basically intact when they fall to the bottom of the mantle.
The Earth’s mantle circulation model shows that Teia will gradually merge into the Earth’s mantle. Since its density is about 2.5% higher than that of the Earth’s mantle, it will sink and solidify, and will eventually stabilize at the lower part of the Earth’s mantle but not merge into the Earth’s core. This is also consistent with This is consistent with the large low-shear wave speed swarms seen today, which are more than 2,000 kilometers deep and about 3% denser than their surroundings.
Researchers say that if we manage to recover some information about the Asiatic planets, we may be able to better understand the structure and composition of the infant solar system.
new paperPublished in the journal Nature.
(Source of first picture:Arizona State University）