The Three-Body Problem

The three-body problem is one of the more vexing problems of classical mechanics. In short, if you have a system of three objects that interact with each other, you can’t use classical Newtonian equations to predict their behavior. Effectively, you have a chaotic system. In astronomy, you might imagine three planets or three stars interacting gravitationally. I first encountered this idea in high school soon after reading how Percival Lowell began a search for a ninth planet in our solar system ...