How sure are we with seismology that the core is solid? Could it have a thick shell with other materials inside? Edit: just found https://www.sciencealert.com/

How sure are we with seismology that the core is solid? Could it have a thick shell with other materials inside? Edit: just found https://www.sciencealert.com/mysterious-donut-structure-found-hidden-inside-earths-core https://www.sciencealert.com/mysterious-donut-structure-foun... very interesting...