It’s not much of a stretch to say that Earth’s inner structure, especially the innermost spherical core, has stupefied scientists for generations. It sits over 3,000 miles below the surface, smaller ...

The Earth's interior is composed of four layers, three solid and one liquid—not magma but molten metal, nearly as hot as the surface of the sun. The deepest layer is a solid iron ball ...

Over time, Earth's interior—which is made mostly of silicate rocks and metals—differentiated into four layers. At the planet's heart lies the inner core, a solid sphere of iron and nickel that ...