Kepler's Laws of Planetary Motion

Kepler's Laws of Planetary Motion describe how planets orbit the Sun. The first law states that planets move in elliptical orbits with the Sun at one focus. The second law, or the law of areas, explains that a planet travels faster when closer to the Sun and slower when farther away, so it sweeps out equal areas in equal times. The third law relates the time a planet takes to orbit the Sun to its distance from it: the farther a planet is, the longer it takes to complete one orbit. These laws reveal the predictable patterns of planetary movements.