Yuan explains that a huge chunk in the Earth’s mantle lies approximately 2,900 kilometers below our feet. The nodules were first detected by seismometers because seismic waves travel slower in the nodules than in the surrounding mantle. These masses are also truly huge, each having twice the mass of the Moon.
It certainly puts into perspective how huge Theia was, and its impact on Earth would undoubtedly have dramatically changed the structure of our planet. A better understanding of Earth’s structure from time immemorial could help us understand more about Earth’s evolution and why it is the only habitable planet in the solar system. All in all, it’s pretty cool to think that there could be debris from another planet buried beneath the surface of our planet.