Inner Core:

the inner core is believed to be made of a solid material, due to extreme pressure which is estimated at 3,600,000 bars compared to 1 bar at the surface.
Both P and S waves move through the inner core, with S waves being generated by P waves at the boundary. This provides good evidence of a solid layer.
The composition of the core is possibly a mixture of iron and nickel which is sometimes referred to as Nife (nickel and iron) based on meteorite evidence. It is believed that the whole solar system formed at the same time from a nebula cloud. Nearly all the material coalesced to make the planets, but some remained to form meteorites and asteroids. The meteorites ar either iron and nickel or silicate (stony).
Iron Nickel is a material with roughly the correct density 12+gm/cm3. There must be dense material at the centre of the earth because the average density of the earth is 5.5gm/cm3 and the average density of the surface rocks is 2.8gm/cm3.

	Created by siobhan.quirk almost 11 years ago

Undergraduate Geology - Part 1 (Earth Structure) Note on The Layers of the Earth, created by siobhan.quirk on 05/11/2013.

The Layers of the Earth