What causes incoming solar radiation?

Incoming solar radiation is primarily caused by the Sun's nuclear fusion processes, which emit energy in the form of electromagnetic radiation, including visible light, ultraviolet, and infrared radiation. This energy travels through the vacuum of space and reaches Earth, where it is absorbed, reflected, or scattered by the atmosphere and surface. The intensity and distribution of this radiation are influenced by factors such as the Earth's distance from the Sun, the angle of sunlight, and atmospheric conditions.