Here's why:
* Lithosphere: The lithosphere is the rigid outermost layer of Earth, composed of the crust and the uppermost part of the mantle. It's relatively cool and rigid.
* Mantle: The mantle lies beneath the lithosphere. It is mostly solid but behaves like a very viscous fluid over long periods. The mantle is much hotter than the lithosphere.
Temperature Gradient: There is a gradual increase in temperature as you go deeper into the Earth. While the lithosphere is relatively cool, the temperature within the mantle increases dramatically with depth.
Key Points:
* The lithosphere is the coolest part of Earth's outer layers.
* The mantle is much hotter than the lithosphere.
* The mantle's heat drives plate tectonics.
Let me know if you have any other questions!
