Is solar energy nuclear fission or nuclear fusion?

Solar energy is nuclear fusion. According to the China Science Popularization Network, the sun is mainly composed of hydrogen and helium elements and can only undergo nuclear fusion. Nuclear fusion is a process of continuous fusion from hydrogen. After fusion, hydrogen will become helium, and during the fusion process. a large amount of energy is released, which is solar energy, which can provide light and provide heat. However, in summer, the temperature will be higher and the human body will feel uncomfortable.