<P> The average density of Earth is 5,515 kg / m . Because the average density of surface material is only around 3,000 kg / m , we must conclude that denser materials exist within Earth 's core . Seismic measurements show that the core is divided into two parts , a `` solid '' inner core with a radius of ≈ 1,220 km and a liquid outer core extending beyond it to a radius of ≈ 3,400 km . The densities are between 9,900 and 12,200 kg / m in the outer core and 12,600 -- 13,000 kg / m in the inner core . </P>
<P> The average density of Earth is 5,515 kg / m . Because the average density of surface material is only around 3,000 kg / m , we must conclude that denser materials exist within Earth 's core . Seismic measurements show that the core is divided into two parts , a `` solid '' inner core with a radius of ≈ 1,220 km and a liquid outer core extending beyond it to a radius of ≈ 3,400 km . The densities are between 9,900 and 12,200 kg / m in the outer core and 12,600 -- 13,000 kg / m in the inner core . </P>
how many layers in the earth 's core
how many layers in the earth 's core
two
two