Parts of the lost planet Theia could be scattered under our feet, causing various anomalies.
They are among the largest and strangest structures on Earth: huge and mysterious masses ( blobs ) of dense rock that lurk deep in the lower parts of our planet’s mantle. Two of these giant masses – called Large Low Shear Speed Provinces (LLSVP) – lie under Africa and the other under the Pacific Ocean.
These anomalies are so massive that they, in turn, generate their own disturbances, such as the great phenomenon currently evolving within and weakening the Earth’s magnetic field, known as the South Atlantic Anomaly.
As for how and why LLSVPs thus came to exist within the mantle, scientists have many ideas, but little hard evidence.
However, what is known is that these giant masses have been around for a long time, and many think that they could have been part of our world since before the giant impact that gave birth to the Moon: ancient traces of the collision between the Earth. and a hypothetical planet called Theia (or Tea).
According to that widely held argument, Theia, the size of Mars, struck the early Earth about 4.5 billion years ago, with much of the Earth and / or Theia possibly fragmenting and becoming the Moon we know today.
As for what happened to the rest of Theia, it is uncertain. Was it destroyed or did it just bounce back into the eternity of space? We do not know.
Some researchers have suggested that the cores of these two primordial planets may have merged into one and that the chemical exchanges brought about by this epic merger are what allowed life to thrive in the resulting world.
Hybrid Hypothesis Regarding The Planet Theia
Now, scientists have returned to these monumental questions with a new proposal, and it is an idea that also reconciles the mysterious LLSVP masses, intertwining them with the hybrid Earth / Theia hypothesis.
According to a new model by researchers at Arizona State University (ASU), LLSVPs may represent ancient fragments of the highly dense, iron-rich mantle of Theia, which sank deep into Earth’s own mantle when the two worlds in development came together, and it has been buried there for billions of years.
“The giant impact hypothesis is one of the most scrutinized models for the formation of the Moon, but direct evidence indicating the existence of the Theia impactor remains elusive,” write the researchers led by first author Qian Yuan, a candidate for Ph.D. studying mantle dynamics at ASU, in a summary of their findings presented last week at the Lunar and Planetary Science Conference .
‘We show that the mantle of Theia can be intrinsically several percent denser than the mantle of Earth, allowing the materials of the mantle of this alien world to sink to the lowest mantle of our planet and accumulate in thermochemical piles that can cause seismically observed LLSVPs. ‘
While there has been speculation for years that LLSVPs may be an alien memory implanted by Theia, the new research appears to be the most comprehensive formulation yet. The findings are currently under review, prior to future publication in Geophysical Research Letters .
Beyond mantle modeling, the results are also consistent with previous research suggesting that certain chemical signatures linked to LLSVPs are at least as primitive as the Theia impact.