Science Topics beginning with ‘L’:
Lagrangian Points are locations in space where the gravitational forces of two relatively massive celestial bodies, such as a star and a planet, or a planet and its moon, balance each other. The combined mass of the two bodies, and their relative motion orbiting about each other, can effect one or more other bodies of much lesser mass. For example, a satelite orbiting the two massive bodies. Refer to the Wikipedia entry: Lagrange Point, for more details.