Hot water or steam from within the earth can be used to heat establishments, or to produce electricity. It is one source of renewable energy because, water can be replenished by the rain, and the heat itself flows consistently from within the earth’s core.

Around 4,000 miles below the earth’s surface, temperatures can reach levels hotter than the sun’s surface. This is where geothermal energy is generated.

The planet is made up of several layers: