[Rockhounds] Scientists Detect Traces of an Ancient Alien World Beneath Earth's Mantle

[Kreigh Tomaszewski]

Some 4.5 billion years or so ago, scientists believe, something big smacked
into Earth and knocked it ass over teakettle.

The result was a bunch of debris, hurled into space, swirling around until
it formed the Moon <https://www.sciencealert.com/moon>. Of the big object,
thought to be the size of Mars <https://www.sciencealert.com/mars>, and
named Theia, nothing much was left. Or so we thought.

Researchers from China, the US, and the UK have uncovered evidence that chunks
of Theia ended up inside the Moon
<https://www.sciencealert.com/we-may-have-finally-found-a-chunk-of-theia-buried-deep-inside-the-moon>.
And evidence also now suggests that chunks of Theia ended up inside Earth,
too.

If that's the case, the giant impact hypothesis could solve a mystery that
has bothered scientists for more than a decade
<https://www.sciencedirect.com/science/article/abs/pii/S0012821X12005109?via%3Dihub>:
the presence of dense, continent-sized blobs of material, buried deep under
Earth's mantle some 2,900 kilometers (1,800 miles) down, curved around its
core.

https://www.sciencealert.com/scientists-detect-traces-of-an-ancient-alien-world-beneath-earths-mantle