What are Lagrange Points?
The Italian-French mathematician Josef Lagrange discovered five special points in the vicinity of two orbiting masses where a third, smaller mass can orbit at a fixed distance from the larger masses. More precisely, the Lagrange Points mark positions where the gravitational pull of the two large masses precisely cancels the centripetal acceleration required to rotate with them. Those with a mathematical flair can follow the link below to a derivation of Lagrange’s result. Of the five Lagrange points, three are unstable and two are stable. The unstable Lagrange points – labelled L1, L2 and L3 – lie along the line connecting the two large masses. The stable Lagrange points – labelled L4 and L5 – form the apex of two equilateral triangles that have the large masses at their vertices. http://www.physics.montana.edu/faculty/cornish/lagrange.
Lagrange points are stable gravitational points in space where an object could be placed and it would remain at a fixed position with respect to a body orbiting the Sun, such as the Earth. Every orbiting planet has five Lagrange points. Earth’s Lagrange points are called L1, L2, L3, L4, and L5. Lagrange points often feature in discussions about space or science fiction because they would be ideal locations to build space stations. Of the Lagrange points, L1 and L2 are located closest to the planet, just 1.5 million km (930,000 mi) closer to the Sun and away from the Sun from the Earth, respectively. This is about five times as far away from the Earth as the Moon is, and would require a trip of roughly two weeks in a modern spacecraft. As the Earth rotates around the Sun, these two points rotate around the Sun with it, always staying in the same place with respect to the planet. These stable orbits are being eyed as places to deploy satellites that observe the Earth-Moon system. Two add
Lagrange points are locations in space where gravitational forces and the orbital motion of a body balance each other. They were discovered by French mathematician Louis Lagrange in 1772 in his gravitational studies of the ‘Three body problem’: how a third, small body would orbit around two orbiting large ones. There are five Lagrangian points in the Sun-Earth system and such points also exist in the Earth-Moon system.
