Sustainable energy or as an energy input for other uses such as cooling equipment. In many climates, a solar heating system can provide a very high percentage (20 to 80%) of domestic hot water energy. Energy received from the sun by the earth is that of electromagnetic radiation. Light ranges of visible, infrared, ultraviolet, x-rays, and radio waves received by the earth through solar energy. The highest power of radiation comes from visible light. Solar power is complicated due to changes in seasons and from day to night. Cloud cover can also add to complications of solar energy, and not all radiation
Ultraviolet communication in butterflies to detect UV light and responds maximally to ultraviolet light at approximately 350 nm. Therefore, a visual pigment that responds to ultraviolet light is the mechanism behind ultraviolet light perception. White Cabbage Butterflies, "Pieris rapae crucivora", use their private ultraviolet communication system to initiate mating behavior. In this species, ultraviolet reflection is sexually dimorphic with females exhibiting the ability to reflect ultraviolet light of 380 nm to 400 nm and males being less able to reflect UV. Males who perceive an ultraviolet reflection from a female initiate a courtship behavior that involves approaching the female and attempting to copulate. Females