Summary
The planet Earth consists of three main layers: the metallic core, the silicate mantle, and the crust. Earth’s outermost layer is a thin shell of solid rock where life flourishes. The crust under oceans, called oceanic crust, is thinner and denser, and continental crust that forms continents is thicker and lighter. The mantle lies beneath the crust and is approximately 2,900 km thick comprising 67% of the total mass of the planet and 84% of its volume. The mantle is mostly solid, but it can flow slowly over long periods of time due to high temperatures and pressures, driving plate tectonics. T
