Lagrangian Points ~ Dr. Roger Wood

Following the spectacular success of Newton’s inverse square law of gravitation applied to planetary orbits, mathematicians spent much of the next 200 years elaborating the theory. In particular, they made many unsuccessful attempts to derive equations that would describe the motions of three masses moving under their mutual gravitation alone – the so called “three-body problem”. In the 18th century, Euler and Lagrange found special case solutions, points in the orbital plane of each planet where a third smaller mass maintains a constant position with respect to the planet as it orbits the Sun – now generally known as Lagrangian points. In the space age, Lagrangian points have received renewed interest as ideal locations for astronomical satellites and as energy-efficient transit points for spacecraft. The astrometric satellite Gaia is currently orbiting in the Sun–Earth Lagrangian point L2, where it will be joined by the James Webb Space Telescope, successor to the Hubble Space telescope, when it is launched later this year. Mention will also be made of the Lagrangian points associated with other solar system planets.