Heat from the Earth
The interior of the Earth is hot, and its temperature increases with depth. Some of the heat is left over from Earth’s earliest days, when the planet was partially molten. But most of the heat is generated today by the energy released when unstable, or radioactive, elements transform themselves into stable elements. The most important of these are uranium, thorium, and potassium. These elements are concentrated in the crust, from which much of Earth’s heat now emanates.
Topic: Earth Science
Subtopic: Earth Structure
Keywords: Earth (Planet)--Crust, Geology, Heat, Radioactive substances