What Is Under The Surface Of The Planet Earth?

The crust is the thin hard layer on the Earth's surface. It is thin compared with the other layers but still between 25 km (15 miles) and 70km (47 miles) thick. Under the oceans, the crust is a lot thinner – only 7 km (4 miles) thick in some places.

The mantle is the next layer and this is 2900 km (1800 miles) thick. It has two regions, an upper one and a lower one. The upper layer layer is more solid and at a lower temperature than the more molten lower layer. Molten rock from the lower layers circulates up to the upper layer and sometimes through breaks in the crust to cause volcanoes.

Deep in the centre of the planet is the core, which is almost one third of the mass of the Earth. Its very dense, hot and made of solid iron and nickel – two metals found on the Earth's surface. It is this core that makes the Earth act like a magnet, so it has a North pole and South pole.

Under the surface is molten lava but before that is a thin layer of crust.