The mantle is approximately 2,900 kilometers (1,802 miles) thick and is primarily composed of rocks rich in magnesium and iron, such as . While it is solid rock, it behaves like an extremely viscous fluid over millions of years—a property known as plasticity. It is generally divided into three main sections:
The mantle is essential for life on Earth for several reasons: Earth’s mantle is
: When mantle rock melts due to changes in pressure or composition, it becomes magma. This magma rises to the surface, creating new landmasses and releasing gases that helped form our atmosphere. The mantle is approximately 2,900 kilometers (1,802 miles)
: The mantle acts as a thermal blanket, slowly releasing the primordial heat from Earth’s formation and the radioactive decay of elements, maintaining the planet's internal temperature balance. This magma rises to the surface, creating new