We started the year with an exciting work in which we peered for the first time into the internal structure of ultra-low-velocity zones (ULVZs) at the bottom of the Earth's mantle (1). Although these enigmatic structures (Figure 1; top) have been known for several decades, we have shown using state-of-the-art waveform inversion (hierarchical, transdimensional Bayesian) that they could be the remains of an ancient magma ocean, formed by the collision of Theia with the proto-Earth. The Moon was then formed from the part that was ejected into space. Many world media reported this result, but I simplified the article here for a broader range of readers: ULVZs – LEFTOVERS OF EARTH’S VIOLENT PAST
This is a companion discussion topic for the original entry at https://www.geo-down-under.org.au/2022-in-a-nutshell/