January 24, 2022
Lagrange points, libration points (lat. librātiō - rocking) or L-points - points in a system of two massive bodies, in which a third body with a negligible mass, which is not affected by any other forces, except for gravitational forces from the first two bodies, can remain motionless relative to these bodies. More precisely, Lagrange points are a special case in solving the so-called restricted three-body problem - when the orbits of all bodies are circular and the mass of one of them is much less than the mass of any of the other two. In this case, we can assume that two massive bodies revolve around their common center of mass with a constant angular velocity. There are five points in the space around them where a third body with a negligible mass can remain motionless in the rotating frame of reference associated with massive bodies. At these points, the gravitational forces acting on the small body are balanced by the centrifugal force. Lagrange points got their name in honor of the mathematician Joseph Louis Lagrange, who was the first to give a solution of a mathematical problem in 1772, from which the existence of these singular points followed.