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 ...

We finally know where two giant blobs in Earth's middle layer came from — and they're a mismatched pair. These strange regions in Earth's mantle, known as "large low velocity provinces" (LLVPs), are ...

There's a lot more to Earth than meets the eye. Far from being just a roundish rock barreling through space, our planet is composed of several layers held together by intense forces of gravity.