Laws of Planetary Motion

Johannes Kepler’s Laws of Planetary Motion describe how planets move around the Sun. The first law states that planets travel in elliptical (oval-shaped) orbits with the Sun at one focus, not a perfect circle. The second law explains that planets sweep out equal areas in equal times, meaning they move faster when closer to the Sun. The third law states that a planet’s orbital period squared is proportional to its distance from the Sun cubed; thus, planets farther away take longer to orbit. These laws reveal the predictable, harmonious motion of planets governed by gravity.