The mantle is a part of an astronomical object. The interior of the Earth, similar to the other terrestrial planets, is chemically divided into layers. The mantle is a highly viscous layer between the crust and the outer core. Earth's mantle is about km ( mi) thick rocky shell that constitutes about 84 percent of Earth's volume. It is predominantly solid and takes over Earth's iron-rich hot core, which occupies about 15 percent of Earth's volume. Past episodes of melting and volcanism at the shallower levels of the mantle have produced a thin crust of crystallized melt products near the surface, upon which we live. The gases evolved during the melting of Earth's mantle have a large effect on the composition and abundance of Earth's atmosphere. Information about structure and composition o