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ATLANTA — Scientists widely agree that an ancient planet likely collided with Earth during its formation billions of years ago, resulting in the formation of our moon.
The giant-impact hypothesis explains many important aspects of the moon and Earth. However, one key question remains: What happened to Theia? Concrete evidence of its existence has been elusive, with no remnants of the planet found in the solar system. Many scientists believed that any debris from Theia would have been mixed into Earth’s interior.
Nevertheless, a new theory suggests that remnants of Theia may still exist beneath the Earth’s surface.
According to a study published in the journal Nature, molten slabs of Theia may have become embedded in Earth’s mantle after the impact and solidified, leaving portions of the ancient planet’s material above Earth’s core, around 1,800 miles below the surface.
A Revolutionary Idea
If this theory is accurate, it would not only provide more details about the giant-impact hypothesis but also answer a longstanding question for geophysicists.
Scientists have already discovered two large low-velocity provinces (LLVPs) deep within the Earth. These massive blobs, one beneath Africa and the other below the Pacific Ocean, are denser than the surrounding mantle and have intrigued researchers for decades.
Qian Yuan, the lead author of the study and a geophysicist at the California Institute of Technology, attended a seminar that detailed the giant-impact hypothesis and clicked with the idea. He realized that the LLVPs could actually be remnants of Theia.
After conducting extensive research and high-resolution modeling, the study concluded that if Theia collided with Earth at a specific size and speed, it could have left behind significant chunks of its material within Earth’s mantle, while also creating the debris that eventually formed our moon.
Interdisciplinary Collaboration
The study involved collaboration between scientists from various disciplines and institutions, including Arizona State, Caltech, the Shanghai Astronomical Observatory, and NASA’s Ames Research Center.
While the theory is not without controversy, with critics citing ongoing research on LLVPs and alternative hypotheses, it presents a compelling argument. The idea that Theia’s remnants are hidden deep within the Earth has captivated the scientific community, although further research is needed to confirm this hypothesis.
In the words of Dr. Seth Jacobson, an assistant professor of planetary science at Michigan State University, “We’ll be debating this for quite some time.”
