Earth's solid inner core may not be solid after all — at least not all the way through. Instead, it’s a hodgepodge patchwork of solid and liquid that reaches all the way to the center.
New research based on the faint echoes of earthquake waves bouncing back to Earth's surface from the depths of the planet suggests that the inner core is more varied than previously appreciated. The findings indicate that the inner core, which grows about a millimeter (0.04 inch) each year as the liquid outer core solidifies, may have grown faster during earlier times in Earth's history. What's more, there may be swirls of liquid iron trapped inside the solid core, study senior author Keith Koper, a seismologist at the University of Utah, said in a statement.
