ABSTRACT
But, their behavior, like that exhibited by the galaxy in the figure above, could
never be modeled by a standard particle system. This is simply because the be-
haviors arise from the complex gravitational interactions that the heavenly bodies
all exert on each other. Because of these attractions, moons orbit planets, planets
orbit their suns, and suns group together to form spiral or globular galaxies. In
turn, the gravity of these galaxies affects all of the other galaxies. The resulting
complex patterns of motion, across many orders of magnitude of scale, could not
possibly arise without the forces of interaction.
