A law firm http://tubegalore.in.net/ tubgalor Earth's innards are presently divided into layers, with the rocky mantle composed mostly of silicates overlying an iron-rich metallic core. How the planet came to have this orderly arrangement is a major mystery, especially since scientists think its beginnings were messy and chaotic, the result of small bodies made up of rock and metals crashing and clumping together shortly after the formation of the sun and the birth of the solar system some 4.5 billion years ago.