Gray (unit) Gray (unit) The gray (symbol: Gy) is a derived unit of ionizing radiation dose in the International System of Units (SI). It is defined as the absorption of one joule of radiation energy per kilogram of matter. It is used as a unit of the radiation quantity absorbed dose which measures the energy deposited in a unit mass at a certain position, and of the radiation quantity kerma, which is the amount of energy that is transferred from photons to electrons per unit mass at a certain position. The corresponding cgs unit to the gray is the rad (equivalent to
Energy (esotericism) 18th and 19th centuries with Mesmer and the magnetism. They continued to be discussed in the 20th century by some thinkers and practitioners in the modern New Age movement. As biologists studied embryology and developmental biology, particularly before the discovery of genes, a variety of organisational forces were posited to account for their observations. German biologist Hans Driesch (1867–1941), proposed entelechy, an energy which he believed controlled organic processes. However such ideas are discredited and modern science has all but abandoned the attempt to associate additional energetic properties with life. According to Brian Dunning, the scientific term energy is, in