Without this moon-sized hunk of iron we wouldn’t exist

Earth’s inner core saved the magnetosphere that keeps our planet liveable.

representation of a coronal mass ejection moving towards earth's magnetic field (magnetosphere)
A coronal mass ejection (CME) reaches Earth as solar particles are deflected away by the planet's magnetic field in this NASA-created image, a still capture from a 4-minute excerpt of "Dynamic Earth: Exploring Earth's Climate Engine," a fulldome, high-resolution movie playing at planetariums around the world / Credit: NASA (CC-BY 2.0)