Potential patches of Earth's ancient crust, sometimes called "sunken worlds," may have just been discovered deep within the mantle, thanks to a new way of mapping the inside of our planet. However, these mysterious blobs appear in places they should not, leaving researchers scratching their heads.
For decades, scientists have been building up a better picture of Earth's interior by using seismographs — 3D images created by measuring how seismic waves from earthquakes reverberate deep within our planet. This method has helped scientists identify ancient sections of the planet's crust, known as subducted slabs, that have been pulled into the mantle through subduction zones where tectonic plates meet. For example, in October 2024, researchers announced the discovery of a section of seafloor that had sunk deep into the mantle below Easter Island.
