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
Southern Pacific class MC-2 pressure, but a lower overall tractive effort. The MC-2 rebuilds included installation of a new 4¼-BL Worthington feedwater heater as well. SP used these locomotives until after World War II, retiring and then scrapping them in 1947 and 1948. The last locomotive of this class was scrapped on April 12, 1949, at SP's Sacramento shops. Southern Pacific class MC-2 Southern Pacific Railroad's MC-2 class of steam locomotives was the first class to be ordered by and built for Southern Pacific (SP) as cab forward locomotives. They were built in 1909 following the design of SP's MC-1 class built earlier that