Kepler's Laws of Planetary Motion:
Further support to the heliocentric model came from the work of Johannes Kepler at around the same time as Galileo's observations. Kepler, a German astronomer, was
trying to work out a theoretical model which explained all observations of planetary motion. The most accurate observations of apparent planetary positions had been made bv Tvcho Brahe.
Brahe invited Kepler to work with him. He recommended that Kepler study the planet Mars because its motion seemed most anomalous, most difficult to reconcile with an orbit made of circles. Further, planets in circular orbits ought to move with constant speed. But Kepler found that their speeds changed with their distance from the Sun. After years of trial and error, he found that the only explanation of the observed movement of Mars was that its orbit was an ellipse with the Sun at one of its foci. Thus, the idea of circular orbits was abandoned. Kepler eventually succeeded in explaining Brahe's observations which could all be expressed simply, in the form of three law$ of planetary motion.
Kepler's laws removed the main objection of the Copernican model, that this model could not give an accurate description of the observed path of the planets. These laws also led to the rejectioli of Pythagorean-Platonic view of the heavens showing only perfect circular motions, which even Copernicus had retained. By.the end of the seventeenth century the heliocentric model of the universe came to be accepted generally. Interestingly, the physical proof of the movement of the Earth came when it was no longer necessary, because by then everybody had already accepted that the Earth moved around the Sun.