Earth’s center may be more complex than thought
DOI: 10.1063/PT.5.028630
BBC : Earth’s inner core may have its own core, according to a new study published in Nature Geoscience. Xiaodong Song of the University of Illinois at Urbana-Champaign and colleagues used the seismic waves generated by earthquakes to look deep into Earth’s center. They found that the inner core, a Moon-sized sphere located some 5000 km below the surface, appears to have two distinct regions. They made that determination based on the orientation of iron crystals in relation to the polar axis: The crystals in the inner inner core are oriented east–west, while those in the outer inner core are oriented north–south. According to the researchers, that difference in alignment suggests something happened in Earth’s past to cause the inner core to rotate.
