Johannes Kepler used the precise observational tables of Tycho Brahe to study planetary motion mathematically. He found a consistent description by abandoning both: Circular motion and Uniform motion. Planets move around the sun on elliptical paths, with non-uniform velocities. Here briefly focus Kepler’s first Laws of Planetary Motion and Kepler’s Third Law. Think critically about Kepler’s Laws: Would you categorize his achievements as physics or mathematics?