Anti-de Sitter space bell. It might be described as being the "opposite" of the surface of a sphere, which has a positive curvature. General relativity is a theory of the nature of time, space and gravity in which gravity is a curvature of space and time that results from the presence of matter or energy. Energy and mass are equivalent (as expressed in the equation "E" = "mc"), and space and time can be translated into equivalent units based on the speed of light ("c" in the "E" = "mc" equation). A common analogy involves the way that a dip in a flat
E=MC² (Mariah Carey album) (BPI), denoting shipments of 100,000 copies. In Japan, the album peaked at number seven on the Oricon Overall Chart, and was certified Gold by the Recording Industry Association of Japan (RIAJ) for shipments of 100,000 copies. After only eight days of release, "E=MC²" was certified Gold in the Philippines, denoting shipments of 15,000 units. The album was the 26th best-selling album worldwide in 2008, according to International Federation of the Phonographic Industry (IFPI). As of September 19, 2009, the album has sold 2.5 million copies worldwide. Credits for "E=MC²" adapted from the album's liner notes. !scope="row"|Worldwide E=MC² (Mariah Carey album)