Mysterious clumps near the Earth’s core have been linked to a collision with another planet

Clumps near Earth’s core are remnants of a collision with another planet, according to a new study. The study suggests that the collision melted most of both planets and led to the formation of the Moon.

Researchers say mysterious clumps lurking more than 1,000 miles underground may be the remains of a Mars-sized planet that crashed into Earth at the dawn of the solar system and unleashed a shower of debris that formed the Moon.

According to scientists’ leading theory, the Moon formed about 4.5 billion years ago when an ancient protoplanet called Theia crashed into the young Earth. At that time, our home planet was still an infant and only about 85% of its current size.

The theoretical impact would melt most of the Earth and Theia, which would reform into a new, larger Earth. Meanwhile, huge amounts of dust and rock were thrown into orbit, where they came together to form the Moon.

While many scientists find the giant impact scenario compelling, the search continues for evidence to support the theory, not least any signs of a violent impact that can still be found today.

With this in mind, an international team of researchers turned their attention to two continent-sized clumps buried deep in the Earth’s mantle, far beneath Africa and the Pacific Ocean. The clumps, known technically as large low-velocity provinces (LLVPs), were initially discovered by seismologists, but their origins were never clear.

The researchers, including Dr Qian Yuan from the California Institute of Technology in Pasadena and Professor Hongping Deng from the Shanghai Astronomical Observatory, part of the Chinese Academy of Sciences, used computer simulations of the giant impact and convection currents within the Earth to explore how the catastrophic event might have unfolded.

According to simulations, the impact would melt the upper half of Earth’s mantle, allowing a hefty chunk of Theia, perhaps 10%, to penetrate deep into the planet and gradually sink toward the core.

Over the next 4.5 billion years, rock from Theia may have moved due to convection within the Earth and eventually formed the clumps present today. The clumps, thought to be slightly denser than surrounding mantle rocks, are near the boundary with Earth’s core, about 1,800 miles below.

“To my knowledge, ours is the first paper to propose this idea,” Dr Yuan told The Guardian. Details were published in the journal Nature.

Scientists may need a significant cache of lunar rocks to figure out whether the buried blobs are indeed remnants of ancient Theia. These rocks could appear in the coming years as space agencies advance their plans to establish a long-term presence on the Moon in preparation for subsequent missions to Mars.

“I look forward to future missions to the Moon to retrieve its mantle rocks, which are very likely to come from the Theia impactor, according to most simulations of the impact on lunar formation,” says Dr. Yuan. “If lunar mantle rock and basalts associated with LLVP have the same chemical signatures, they should both come from Theia.”

Professor Alex Halliday, who studies planetary evolution and materials at the University of Oxford, praised the work but said there was more work to be done on the idea – particularly on the processes that led to the diverse composition of the deep mantle, as well as similar isotopic signatures between Earth and Earth. Moon.

“This is an excellent paper with bold thinking and interesting conclusions,” he said. “However, this raises questions that require further discussion and analysis, especially regarding how the Moon and Earth mixed to achieve such great similarities while maintaining ancient heterogeneity in the deep mantle.”