Kepler's Laws
Kepler's Laws are a set of three fundamental principles in Astronomy that describe the motion of Planets around the Sun. These laws were formulated by Johannes Kepler, a German mathematician and astronomer, based on his analysis of Tycho Brahe's precise measurements of planetary orbits. The first law states that the orbits of planets are elliptical in shape, with the Sun at one of the two Focus (geometry) points. The second law describes the speed of a planet as it orbits the Sun, stating that the line connecting the planet to the Sun sweeps out equal areas in equal times. The third law relates the size of a planet's orbit to its orbital period, showing that the square of the period is proportional to the cube of the semi-major axis.