Earth’s Inner Core May Have an Inner Core

Earth's core consists of a solid iron-nickel ball rotating within a layer of liquid metal.But that ball may not be as simple as it seems: new research suggests the inner core contains its own inner core.If so, this so-called innermost inner core may record an early phase in Earth's evolution.Earth scientists have long observed that seismic waves from earthquakes move differently through the heart of the inner core than they do through its upper layers, indicating some sort of change in texture.

Read at Scientific American