posted by Rob .
Explain how redioactive decay has always warmed the Earth from the inside and how nuclear fusion has always warmed the Earth from the outside.
drwls in Sloveina
The slow radioactive decay of elements like Uranium that are still present in the earths crust generates heat from within. The fusion of hydrogen into helium in the sun, through a series of steps that also involve carbon and oxygen transmutation, provides the energy that keeps the surface of the earth warm