The Earth has a layered structure made up of the core ... Wegener could not correctly explain what caused the continents to move but his ideas eventually led to modern theories of plate tectonics.

Earth is about 4.5 billion years old. Scientists think that by 4.3 billion years ago, Earth may have developed conditions suitable to support life. The oldest known fossils, however, are only 3.7 ...

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 ...