Aether (classical element)
According to ancient and medieval science, aether (Greek: αἰθήρ aithēr), also spelled æther or ether, also called quintessence, is the material that fills the region of the universe above the terrestrial sphere. The concept of aether was used in several theories to explain several natural phenomena, such as the traveling of light and gravity. In the late 19th century, physicists postulated that aether permeated all throughout space, providing a medium through which light could travel in a vacuum, but evidence for the presence of such a medium was not found in the Michelson–Morley experiment.
Mythological origins
The word αἰθήρ (aithēr) in Homeric Greek means "pure, fresh air" or "clear sky". In Greek mythology, it was thought to be the pure essence that the gods breathed, filling the space where they lived, analogous to the air breathed by mortals. It is also personified as a deity, Aether, the son of Erebus and Nyx in traditional Greek mythology. Aether is related to αἴθω "to incinerate", and intransitive "to burn, to shine" (related is the name Aithiopes (Ethiopians; see Aethiopia), meaning "people with a burnt (black) visage"). See also Empyrean.
