N-body problem

The two-body problem is simple; its solution is that each body travels along a conic section which has a focus at the centre of mass of the system.

The three-body problem is much more complicated; its solution can be chaotic. The general three-body problem has not been solved analytically, although approximate[?] solutions can be calculated by numerical methods or perturbation methods.

A restricted three-body problem, in which two of the bodies are in circular orbits and the third is of negligible mass (approximated by the Sun - Earth - Moon system) was solved analytically by Lagrange in the 18th century. The points where the smallest object can orbit the other two with the same period are called Lagrangian points.

External Link

• More detailed information on the 3-body problem (http://www.geom.umn.edu/~megraw/CR3BP_html/cr3bp)