A two-body system refers to a physical system consisting of two distinct objects that interact with each other through gravitational, electromagnetic, or other forces. Common examples include a planet orbiting a star, such as the Earth and the Sun, or two stars in a binary star system. The behavior of these systems can often be analyzed using Newton's laws of motion and the law of universal gravitation. In a two-body system, the motion of each body can be described relative to the other. This means that the center of mass of the system remains constant if no external forces act on it. Understanding two-body systems is essential in fields like astrophysics, mechanics, and celestial navigation.