Kepler’s Laws of Planetary Motion

1. Kepler's First Law (The Law of Ellipses): Each planet moves in an elliptical orbit, with the sun at one focus of the ellipse. This law is also known as the law of elliptical orbits and obviously gives the shape of the orbits of the planets around the sun.
2. Kepler's Second Law(The Law of Equal Areas): The radius vector, drawn from the sun to the planet, sweeps out equal areas in equal time, i.e., its areal velocity (or the area swept out by it per unit time) is constant. This is referred to as the law of areas and gives the relationship between the planet's orbital speed and its distance from the sun.
3. Kepler's Third Law(The law of Harmonies): The square of the planet's period (T) is proportional to the cube of its orbit's semi-major axis (R). This is known as the harmonic law, which states the relationship between the size of the orbit of a planet and its time of revolution.
   T² ∝ R³
   

Significance of Kepler's Laws:

The three laws of Kepler's planetary motion were groundbreaking because they provided an accurate model for planetary motion without relying on epicycles or circular orbits. They later became a foundation for Newton's law of universal gravitation, which explained why these laws hold true by linking them to gravitational forces.