Which astronomer formulated the three laws of planetary motion?

Johannes Kepler formulated the three laws of planetary motion. Published between 1609 and 1619, the laws describe how planets move around the Sun and replaced the ancient assumption that their orbits had to be perfect circles.

Kepler used the exceptionally accurate observations collected by the Danish astronomer Tycho Brahe, especially measurements of Mars. His first law states that planets travel in ellipses with the Sun at one focus. The second says that a line joining a planet and the Sun sweeps out equal areas in equal times. The third relates the square of a planet’s orbital period to the cube of its average distance from the Sun.

Kepler supported the Sun-centered model associated with Copernicus, but he did not make the original heliocentric proposal. Galileo later supplied telescopic observations that supported heliocentrism, while Isaac Newton showed how Kepler’s laws followed from universal gravitation. Their work formed a bridge between observational astronomy and modern physics.