Scientists reckon they can reveal Earth’s deepest secret – a new “inner-inner core”. So what? It’s been thought that Earth has 4 main layers: the crust, the mantle, the outer core and the inner core. And while the idea of an additional distinct layer isn’t new, it’s never been stacked up. But Australian National Uni researcher Joanne Stephenson says her team has devised a “very clever” algorithm that has found it. Stephenson is interested in the core because its interactions create Earth’s magnetic field, shielding the planet and allowing life to exist here. So, it’s pretty important… Researchers believe the study could point to a more complex story of Earth’s formation than previously thought and warrant textbooks’ rewriting.