Quakes reveal secrets of Earth’s inner core

Measurements of earthquake reverberations have revealed that our planet’s inner core — a solid ball of iron nickel — has two distinct layers made mainly of differently structured iron crystals. The way these oscillations are distorted as they bounce back and forth through the centre of the planets allowed his team to figure out the core’s structure. The finding will help researchers to understand how the core formed millions of years ago and what role it might have had in shaping the magnetic field.