Transcript: Energy produced in the core of the Sun travels out using two of the three basic modes of heat transport. Helium exists in the core, but some is found further out because it preexisted in the solar nebula and it has had time to diffuse out from the core where it’s generated by fusion. Throughout most of its volume energy travels outward in the Sun by radiation, electromagnetic waves of different frequencies and wavelengths. In the outer quarter of its radius the temperature difference is so large that energy cannot move fast enough by radiation so convection occurs. In convection, pockets of hot gas rise and then fall and carry energy outwards, much as happens in a pan of boiling water.