Scientists have found that Earth’s deep mantle may hold pieces of the ancient planet Theia, offering new insights into the Moon’s origin and Earth’s formative years.
The study, which relied on computational fluid dynamics methods pioneered by Prof. Hongping Deng of the Shanghai Astronomical Observatory of the Chinese Academy of Sciences, was published as a featured cover in the journalThe formation of the Moon has been a persistent enigma for several generations of scientists. The prevailing theory has suggested that, during the late stages of Earth’s growth approximately 4.
Since Gaia and Theia were relatively independent formations and composed of different materials, the theory suggested that the Moon—being dominated by Theian material—and the Earth—being dominated by Gaian material—should have distinct compositions. However, high-precision isotope measurements later revealed that the compositions of the Earth and Moon are remarkably similar, thus challenging the conventional theory of Moon formation.To further refine the theory of lunar formation, Prof.
“Our findings challenge the traditional notion that the giant impact led to the homogenization of the early Earth,” said Prof. Deng. “Instead, the Moon-forming giant impact appears to be the origin of the early mantle’s heterogeneity and marks the starting point for the Earth’s geological evolution over the course of 4.5 billion years.”
Dr. Qian Yuan from the California Institute of Technology, along with collaborators, proposed that LLVPs could have evolved from a small amount of Theian material that entered Gaia’s lower mantle. They subsequently invited Prof. Deng to explore the distribution and state of Theian material in the deep Earth after the giant impact.
The research team also calculated that this Theian mantle material, similar to lunar rocks, is enriched with iron, making it denser than the surrounding Gaian material. As a result, it rapidly sank to the bottom of the mantle and, over the course of long-term mantle convection, formed two prominent LLVP regions. These LLVPs have remained stable throughout 4.5 billion years of geological evolution .