Scientists discover remains of hidden ‘buried planet’ under Earth surface from 4.5 billion years ago
The planet was long thought to have disappeared during the collision.
Before we start packing our bags to prepare for life on Mars or the Moon, there's still a lot to uncover about our home planet. As well as discovering what's missing.
According to new research, parts of the Earth's crust are missing. Scientists also noted the fascinating remnants from an ancient planet located close to the Earth's core.
Our understanding of how our moon came to be involved in a collision between Earth and a smaller planet called Theia - a theory planetary scientists have called the 'giant impact'.
However, no remains of this smaller planet have ever been found, which has puzzled scientists for years, until now.
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The new evidence of this event points to two mysterious blobs beneath the surface, hinting that our home planet could have absorbed Theia.
The blobs, known as large low-velocity provinces (LLVPs), were first discovered in the 1980s, under the continent of Africa and the Pacific Ocean.
Their high iron content means that the seismic waves passing through are slowed down, leading to their descriptive name.
Qian Yuan, O.K. Earl Postdoctoral Scholar Research Associate and leader of the research noted these as 'mantle blobs.'
'Seismic images of Earth’s interior have revealed two continent-sized anomalies with low seismic velocities, known as the large low-velocity provinces (LLVPs), in the lowermost mantle,' the researchers wrote.
'The LLVPs are often interpreted as intrinsically dense heterogeneities that are compositionally distinct from the surrounding mantle.'
They added: 'Here we show that LLVPs may represent buried relics of Theia mantle material (TMM) that was preserved in proto-Earth’s mantle after the Moon-forming giant impact.
'Our canonical giant-impact simulations show that a fraction of Theia’s mantle could have been delivered to proto-Earth’s solid lower mantle.'
Paul Asimow, the Eleanor and John R. McMillan Professor of Geology and Geochemistry, who also worked on the research, said: 'A logical consequence of the idea that the LLVPs are remnants of Theia is that they are very ancient.'
Looking at the next steps, Asimow added: 'It makes sense, therefore, to investigate next what consequences they had for Earth's earliest evolution, such as the onset of subduction before conditions were suitable for modern-style plate tectonics, the formation of the first continents, and the origin of the very oldest surviving terrestrial minerals.'