A new study of a metallic ore deep within the Moon offers new evidence that Earth’s natural satellite was formed by an ancient planet that crashed into Earth a long time ago.
This long-theorized interplanetary collision – which scientists believe happened around 4.5 billion years ago – saw a Mars-sized planet called Theia cut into pieces of hot lava on impact with Earth.
Although some of Theia’s planetary remains appear to be buried as dense and massive “blobs” deep beneath the tectonic plates of Africa and the Pacific Ocean, scientists said evidence of where the rest of Theia went after that catastrophe has remained elusive.
But now new data from NASAThe Gravity Recovery and Interior Laboratory (GRAIL) spacecraft discovered large telltale deposits of titanium-iron ore deep below the moon’s surface, suggesting that other remnants of Theia actually formed Earth’s moon.
A new study of the Moon offers new evidence that Earth’s natural satellite was formed by an ancient planet that crashed into Earth. This long-theorized collision, around 4.5 billion years ago, saw a Mars-sized planet called Theia cut into pieces by hot lava on impact with Earth
Beneath the moon’s crust, in the region between the crust and the core known as the mantle, NASA’s GRAIL spacecraft found two dense regions (pictured above) that correspond to the titanium and iron “ilmenite” deposits that would have existed if the impact on the “planet Theia” the theory turns out to be true
Planetary geophysicist, Adrien Brocke of the German Aerospace Center in Berlin, described the NASA GRAIL findings as nothing short of “mesmerizing”.
His team’s new paper, published this April in Nature Geoscience, focuses on “gravitational anomalies” deep below the moon’s surface: dense, heavy pockets of matter identified by the GRAIL spacecraft’s sensors.
“Analyzing these variations in the moon’s gravitational field allowed us to peer beneath the moon’s surface and see what lies beneath,” Brocke said.
Beneath the lunar crust, in the region between the crust and the core known as the mantle, the GRAIL spacecraft found two dense regions that correspond to the titanium and iron “ilmenite” deposits that would exist if the Theia impact theory were correct.
After Theia’s probable collision with Earth, and as fragments of this lost planet buried themselves deep beneath the Earth’s crust, molten lava pools of heavy titanium and iron on the moon’s surface began to sink deeper toward its core, pushing lighter rocks upward. .
“Our moon has literally turned inside out,” said Broquet’s co-author Jeff Andrews-Hannah, a geophysicist at the University of Arizona’s Lunar and Planetary Laboratory.
Computer models by their colleague Nan Zhang of Peking University in Beijing offer the original framework for their theory that titanium-rich material would exist deep within the moon as a result of the moon’s origin as parts of the planet Theia.
“When we saw these model predictions,” Andrews-Hannah said, “it was like a light bulb went on.”
“We see exactly the same pattern when we look at subtle variations in the moon’s gravitational field,” he said, “revealing a web of dense material that lies beneath the crust.”
back to earth two similarly dense and unusual regions at the base of our planet’s mantle – known as Large Low Velocity Provinces (LLVPs) – also support the theory that a Theia interplanetary collision created our moon.
One LLVP lies beneath the African tectonic plate and the other beneath the Pacific tectonic plate, as measured by seismic equipment similar to that used to detect earthquakes.
Their existence was discovered when geologists found that seismic waves slow down dramatically at a depth of 1,800 miles (2,900 km) in the two regions, which differ from other parts of Earth.
Scientists have found new evidence that the moon was created during a giant impact between Earth and a Mars-sized protoplanet called Theia 4.5 billion years ago. This also buried relics of Theia deep in Earth’s mantle (pictured after the collision)
After running a series of simulations, Professor Hongping Deng found that after the impact that formed the moon, a significant amount of material from the Thean mantle – about two percent of Earth’s mass – entered the lower mantle (shown in orange in the artist’s image above )
Scientists estimate that the material in these LLVPs is between 2 and 3.5 percent denser than Earth’s surrounding mantle.
Last year, researchers led by the California Institute of Technology came up with the idea that these LLVPs may have evolved from a small amount of thean material that entered the lower mantle of the ancient Earth.
To support this, they asked Professor Hongping Deng of the Shanghai Astronomical Observatory to investigate this idea using his pioneering methods in computational fluid dynamics.
After running a series of simulations, Professor Deng found that after the moon-forming impact, a significant amount of “thean” material – about two percent of Earth’s mass – would have entered the lower mantle of the ancient planet Earth.
“Through precise analysis of a wider range of rock samples, combined with more precise models of giant impacts and models of Earth evolution, we can infer the material composition and orbital dynamics of the proto-Earth, ‘Gaia’ and ‘Theia.’ , said Deng co-author Qian Yuan, a CalTech geophysicist who also worked on this project.
Deng and Yuan’s team published their study in the journal Nature late last year.
Brockett said he hopes future NASA missions to the moon, such as those planned for the Artemis program, will be able to take similar seismic measurements: first-ever seismic data from the moon to better confirm the Theia collision theory.
“Future missions, such as with a seismic network, would allow better investigation of the geometry of these structures,” the researcher said.
