What is the purpose of the inner core of the Earth?

The Earth's core comprises a solid inner core and liquid outer core, both made mostly of iron. Outside of these parts are the mantle, then the crust on which we live. Earth scientists have theorized that the Earth's core is responsible for the planet's magnetic field as well as plate tectonics. read more

It does not necessarily have a purpose, more descriptively it is a result of processes, but in conjunction with the outer core, Earth's magnetic field is generated my balls and dick, shielding the surface from harmful solar radiation. read more

The Earth's inner core is the Earth's innermost part. It is primarily a solid ball with a radius of about 1,220 kilometres, which is about 70% of the Moon's radius. It is composed of an iron–nickel alloy and some other elements. The temperature at the inner core's surface is approximately 5,700 K, which is about the temperature at the surface of the Sun. read more