There is an alien planet inside Earth

Shortly after the formation of the solar system, 4.6 billion years ago, the Mars-sized celestial body Theia collided with the primordial Earth. Our moon was formed from the debris thrown into space – a mixture of matter from Theia and the original Earth. Remains of Theia are also preserved deep in the Earth’s mantle, as a research team from the US and Britain has now discovered.

Two previously mysterious regions of increased density can be explained as accumulations of Theia matter, the scientists write in the journal Nature.

“Seismic studies of the Earth’s interior reveal two continent-sized regions in which seismic waves propagate unusually slowly,” explain Qian Yuan of Arizona State University and his colleagues.

The areas deep in the Earth’s mantle therefore differ in composition from the surrounding material of the Earth’s mantle and are two to three and a half percent denser. To date, there is no generally accepted scientific explanation for these regions.

Using extensive computer simulations, Yuan and his colleagues now show that such denser regions are a natural consequence of large collisions during planet formation.

They also show that the two anomalies, located deep in the Earth’s mantle beneath the Pacific Ocean and beneath Africa, may be remnants of Theia. “Our simulations of the collision show that part of Theia’s mantle may migrate into Earth’s lower mantle,” the researchers said.

Based on the composition of the moon, which was formed from soil and Theia debris, Yuan and his colleagues obtain a density for these sinking fragments of the Theia mantle that is two to three and a half percent higher than that of Earth’s normal mantle – in good agreement with the results. Values ​​derived from seismic surveys.

As the team’s simulations also show, these are fragments of the Theia mantle up to fifty kilometers in size that have sunk into the Earth’s interior and coalesced into larger structures above the Earth’s core.

An important aspect is that these larger compactions in the Earth’s mantle can remain stable for four and a half billion years, until today, as the computer models show.

And there’s another piece of evidence that supports Yuan and his colleagues’ hypothesis: The Hawaiian Islands contain a form of volcanic basalt whose composition is surprisingly similar to the rocks of the moon’s lava plains.

This rock may have come from the region of Theia matter, deep beneath Hawaii.

But Yuan and his colleagues’ model is not only important for the Earth-moon system. “Major collisions often occur in the final phase of planet formation,” the researchers emphasize.

“It is therefore likely that similar inhomogeneities exist in the interiors of other planets.” And there may even be traces of even earlier collisions within the Earth.

Recently, studies of lunar dust brought to Earth by the astronauts of the Apollo 17 mission have shown that Earth’s satellite is at least 4.46 billion years old.

This means that Earth’s satellite is 40 million years older than assumed based on the best previous measurements, an international research team reports in the journal ‘Geochemical Perspectives Letters’. The material was first examined using the so-called tomographic atomic probe. This is a microscope technique that allows three-dimensional data about atoms to be displayed.