What is the innermost layer of the Earth called?

What is the innermost layer of the Earth called? It is the inner core. This central region is a solid sphere made mainly of iron and nickel, surrounded by the liquid outer core and beneath the mantle.

The inner core remains solid despite temperatures comparable to the Sun’s surface because pressure at Earth’s center raises the melting point of iron. Scientists cannot sample it directly; they study it through earthquake-generated seismic waves and Earth’s magnetic field. Shear waves passing through the inner core provide evidence that it is solid.

Danish seismologist Inge Lehmann inferred the inner core’s existence in 1936 after studying earthquake seismograms. It has an estimated radius of about 1,221 kilometers, roughly 19% of Earth’s radius. A common mix-up is calling the outer core the innermost layer: the outer core is closer to the center than the mantle, but the solid inner core lies inside it. Convection in the liquid outer core helps generate Earth’s magnetic field.