Black Holes: Facts, Theory & Definition. Black holes are some of the strangest and most fascinating objects found in outer space. They are objects of extreme density, with such strong gravitational attraction that even light cannot escape from their grasp if it comes near enough.
Chemigation is the injection any chemical such as nitrogen, phosphorus or a pesticide into irrigation water and applied to the land using the irrigation system. The proper use of chemigation is recognized as a Best Management Practice (BMP) for irrigated agriculture.
Chemiluminescence (sometimes  chemoluminescence ) is the emission of light (luminescence), as the result of a chemical reaction.There may also be limited emission of heat. Given reactants A and B, with an excited intermediate â ,t is the antithesis of a photochemical reaction, in which light is used to drive an endothermic chemical reaction. Here, light is generated from a chemically exothermic reaction. A standard example of chemiluminescence in the laboratory setting is the luminol test.