The Earth: Core, mantle and crust

The Earth's core, mantle and crust are chemically and physically distinct. The internal structure and properties of the Earth have been deduced using an array of remote methods including seismology, gravity, electromagnetic and other geophysical methods, geochemistry and mathematical modelling. The lithosphere, comprising the crust and uppermost part of the mantle, is the Earth's cool and mechanically strong outer boundary layer. Below the lithosphere is the convecting mantle, often sub-divided into the upper mantle and the lower mantle. The Earth's core is iron-rich, with a solid inner core surrounded by a liquid outer core. A convective dynamo generates the magnetic field - this operates through the interaction of convective motions in the electrically conducting outer core, the presence of the solid inner core and magnetic fields within the cooling Earth.