Kepler's Laws

Explore planetary motion with three fundamental laws

Kepler's First Law: planets orbit in ellipses with the Sun at one focus. Second Law: a line joining a planet and the Sun sweeps equal areas in equal times — meaning planets move faster near perihelion. Third Law: T² = (4π²/GM)a³, so the orbital period depends only on the semi-major axis. These laws were derived empirically by Kepler and later derived from Newton's law of gravity.