Kepler’s Laws
Planetary motion had been observed by astronomers since ancient times. Before Galileo, all observations of the planet’s positions were made with naked eyes. By the 16th century a lot of data were available about planetary positions and motion. Johannes Kepler, studied these data. He noticed that the motion of planets follows certain laws. He stated three laws describing planetary motion. These are known as Kepler’s laws
Kepler's first law:
The orbit of a planet is an ellipse with the Sun at one of the foci.
Kepler's Second law:
The line joining the planet and the Sun sweeps equal areas in equal intervals of time
Kepler's Third law :
The square of its period of revolution around the Sun is directly proportional to the cube of the mean distance of a planet from the Sun.
= Video Lecture on Kepler's law
