Question: Why is earths core fiery?

Eoin Carley answered on 19 Nov 2014:

Hello! This question is still puzzling scientists, but there are some nice theories out there. When the Earth formed it was extremely hot and full of molten rock. Eventually the outer layers solidified, but the inner part of the Earth still has some of the original heat. Even after 4.5 billion years, the Earth has still not cooled down! There is also another source of Earth’s heat – radioactivity. There is a lot of radio active materials in the Earth’s core and they give off a lot of heat.