Which scientist developed the three laws of planetary motion?

Johannes Kepler developed the three laws of planetary motion. Working in the early 17th century, he used exceptionally precise astronomical observations to replace circular planetary orbits with elliptical ones.

Kepler's first law states that planets move in ellipses with the Sun at one focus. His second law says that a line joining a planet and the Sun sweeps out equal areas in equal times, meaning a planet moves faster when closer to the Sun. His third law relates a planet's orbital period to its average distance from the Sun.

Kepler published the first two laws in Astronomia nova in 1609 and the third in Harmonices Mundi in 1619. The observations came chiefly from Tycho Brahe, whose measurements of Mars were accurate enough to reveal that a circular model could not fit the data.

Isaac Newton later showed that Kepler's laws follow from universal gravitation and mechanics. Copernicus proposed a Sun-centered system, and Galileo defended it, but Kepler supplied the mathematical laws describing planetary motion.