Drunken solution to the chaotic three-body problem
— Read on phys.org/news/2021-12-drunken-solution-chaotic-three-body-problem.html

When one massive object comes close to another, their relative motion follows a trajectory dictated by their mutual gravitational attraction, but as they move along and change their positions along their trajectories, the forces between them, which depend on their mutual positions, also change, which, in turn, affects their trajectory. For two bodies (e.g., the Earth moving around the sun without the influence of other bodies), the orbit of the Earth would continue to follow a specific curve (an ellipse), which can be accurately described mathematically. However, under the influence of a third object, the complex interactions lead to the three-body problem—the system becomes chaotic and unpredictable, and the system’s evolution over long time scales cannot be predicted. Indeed, while this phenomenon has been known for over 400 years, ever since Newton and Kepler, a neat mathematical description for the three-body problem is still lacking.