N-Body Problem in 2D
This Demonstration shows a two-dimensional version of the -body problem, in which different masses interact gravitationally. In order to predict their motions, a system of coupled differential equations must be solved consistent with a set of initial conditions for positions and velocities that are chosen at random.
The equations of motion are:
where is the acceleration of the body , is the gravitational constant, is the mass, and is the vector connecting masses and .
 M. Trenti and P. Hut, "N-Body Simulations (Gravitational)," Scholarpedia, 3(5):3930, 2008. www.scholarpedia.org/article/N-body_simulations _ %28 gravitational %29.