Most of the world’s energy resources are from the sun’s rays hitting earth - some of that energy has been preserved as fossil energy, some is directly or indirectly usable e.g. via wind, hydro or wave power. The term solar constant is the amount of incoming solar electromagnetic radiation per unit area, measured on the outer surface of Earth’s atmosphere, in a plane perpendicular to the rays. The solar constant includes all types of solar radiation, not just visible light. Read More   read more »