Click each layer to drill down through the Earth! From thin crust to the blazing hot inner core — 6,371 km deep!
We've never drilled more than 12 km into the Earth (the Kola Superdeep Borehole). So how do scientists know what's inside? They study seismic waves from earthquakes! Different waves travel at different speeds through solids and liquids, revealing the Earth's internal structure.
Earth's core is roughly the size of Mars. The outer core's liquid iron generates Earth's magnetic field — without it, solar winds would strip away our atmosphere, making Earth uninhabitable.