Lagrangian Point

When one body orbits around another, there exist points of equilibrium in their environment where the gravitational attraction of one is counterbalanced by that of the other. Celestial mechanics names these areas of equilibrium Lagrangian points. When an object of low mass, such as a satellite, is placed in one of the Earth-Sun system’s Lagrangian points, its position relative to the Earth and the Sun remains fixed. The Lagrangian point L1 where the SOHO satellite is found is situated in between the Earth and the Sun, at 1.5 million kilometres from the Earth.