The Earth’s mantle is primarily solid, but it behaves like a very viscous fluid over long periods of time. This layer, which lies between the Earth’s crust and outer core, is composed of silicate minerals that can flow slowly due to the intense heat and pressure found at these depths.
The mantle extends to about 2,900 kilometers (1,800 miles) below the Earth’s surface and plays a crucial role in tectonic activities. Although the solid nature of the mantle gives the Earth its structural integrity, the ability of the mantle material to flow is what drives plate tectonics and contributes to phenomena like earthquakes and volcanic activity.
In summary, while the Earth’s mantle is predominantly solid, its unique properties allow it to flow over geological time scales, making it essential for the dynamic processes that shape our planet.