Theia’s influence on Earth was created by the Moon – and perhaps left a bit of shrapnel behind.
There are two giant patches of dense material lurking in the lower depths of the Earth’s mantle beneath West Africa and the Pacific Ocean. Thousands of miles wide, the spots are one of the best-kept secrets on the planet – and have puzzled scientists for decades.
There is now growing evidence that the spots could be the remnants of fragments of an ancient protoplanet named Theia that crashed on Earth about 4.5 billion years ago, Science Magazine reports. Scientists previously suspected that there was a link between the spots, formally known as large low-shear provinces (LLSVP), and the Moon, but most thought LLSVPs were planetary scars from Theia’s impact, not parts of the extraterrestrial world itself.
To be honest, this isn’t the first time scientists have assumed that underground spots are the remains of Theia, Science reports. But Qian Yuan, a graduate of Arizona State University who presented the idea at last week’s scientific conference on lunars and planets, seems to have been the most compelling case to date.
“I think it’s entirely feasible until someone tells me it’s not,” Arizona state seismologist Edward Garnero, who did not work on the study, told Science.
The smoking rifle in Yuan’s work, such as, is seismological evidence that LLSVPs are chemically different from the rest of the mantle rocks that surround them. This suggests that the spots are of extraterrestrial origin – and since they are six times more massive than the Moon, something as large as a protoplanet would have to remove them.
Although the research remains somewhat speculative, seismologists encouraged by studies such as Yuan’s are increasingly convinced that other parts of Earth’s shrapnel could be hiding beneath the Earth’s surface, according to Science. Their discovery, they suspect, could help reveal that the ancient past of the Earth was much more violent than what we know so far.
READ MORE: The remnants of the shocks that created the Moon can lie deep in the Earth [Science Magazine]
More about the Earth’s layers: Scientists: Something is hiding in the center of the Earth’s core
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