An Alien World Might Be Hiding Inside Earth, Study Says

06:04 16/09/2022

The Arizona State University scientists identified specific areas of the Earth’s interior and modeled the process by which these areas could have crashed with early Earth and sunk into its center:

According to a study, Earth was formed by a Mars-sized rogue planet known as Theia, with identifiable fragments of the alien planet still located in Earth’s interior.

The moon was formed by the same catastrophic impact, according to scientists, but this is the first time they’ve analyzed the specific remains of the collision that remain in the Earth’s mantle.

In 2016, UCLA researchers proposed that Earth is actually two planets that crashed and fused together: itself and Theia. At the time, scientists said they believe the two planetary masses mixed together uniformly. Qian Yuan of Arizona State University and his colleagues now propose that the mysterious dense areas in Earth’s interior are the remaining pieces of Theia.

Yuan’s team delivered a paper at the 52nd Lunar and Planetary Science Conference earlier this month. They explain in it:

“Here, we demonstrate that Theia’s mantle may be several percent intrinsically denser than Earth’s mantle, which enables the Theia mantle materials to sink to the Earth’s lowermost mantle and accumulate into thermochemical piles that may cause the seismically-observed [dense areas].”

These dense zones are referred to as “continent-sized Large Low Shear Velocity Provinces (LLSVPs).”

The Arizona State University scientists identified specific areas of the Earth’s interior and modeled the process by which these areas could have crashed with early Earth and sunk into its center:

“We define successful models in which the [Theia mantle materials] sink to the lowermost mantle and form into spatially isolated thermochemical piles that occupy 3-15% area of the 2D model domain, similar to the present-day LLSVPs which occupy ~3-9 vol% of the Earth’s mantle.”

In an interview with Vice, Yuan described receiving a bolt of inspiration after discussing LLSVPs with a colleague. “When I got back to my office,” Yuan said, “I just did a very easy calculation where I compared the size of the LLSVPs to the mantle of Mars, because Theia was believed to be very similar to Mars. The total mass of the moon, together with the LLSVPs, is almost perfectly matched with [Mars’s] mantle.”

How did the dense Theia materials survive for billions of years? It’s due to the way the Earth’s mantle functions, in which convection circulates materials of a certain temperature and density. Because the Theia materials were so dense, they sank and never resurfaced in the convection zone. Consider this to be the debris that builds in a sharp corner that is difficult to reach with a vacuum cleaner.

What does it mean for these materials to remain deep inside the Earth? Because “continent-sized” areas make up the majority of the Earth’s interior, understanding how they formed and how they endure could assist in the progress of Earth science. According to HuffPost, these two massive portions are hundreds of miles thick and are located beneath West Africa and the Pacific Ocean.

Because of their likely shared genesis story, these dense mantle parts and the moon may have interesting parallels to explore. How frequently can you compare one 4.5-billion-year-old rock sample orbiting in space to another sunk into the planet’s core? It’s a scientific method dream come true.

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