The layers of the Earth কী?

The Earth is made of three main layers, from the surface to the centre:

• the crust, a thin outer layer of solid rock, a few kilometres to a few tens of kilometres thick;
• the mantle, a thick layer of hot, dense, solid rock, down to a depth of about 2900 km;
• the core, made of metal, mostly iron with some nickel, from about 2900 km down to the centre. The core has two parts: the outer core, which is liquid, and the inner core, a solid ball at the centre, about 1220 km in radius.