Principle of Least Action

The Principle of Least Action is a fundamental idea in physics stating that the natural path a system takes between two states is the one that minimizes a quantity called "action," which depends on the system's motion and energy over time. In essence, particles and objects move in a way that requires the least effort or "cost" to transition from start to finish. This principle helps explain the behavior of physical systems, such as how planets orbit or how light bends, by showing that nature prefers the most efficient, optimal route.