Galileo Galilei was a Italian physicist, mathematician, astronomer and philosopher; who planed a major role in the scientific revolution. Albert Einstein called him 'The Father of Modern Science'.
Initially he was a medical student but did nit complete his degree, as he was interested in mathematics. In 1589, he was appointed as professor in mathematics at Pisa. He demonstrated his first telescope on 15 August, 1609. He confirmed the phases of venus and discovered four largest satellites of Jupiner, later named 'Galilean Moons' in his honour. He introduced concept of acceleration in physics and proved experimentally that time taken by freely falling bodies to reach ground in independent of mass of the body.
He opined that the earth revolves around the sun and not the sun around the earth. This was against the opinion and faith of the Church, hence church authority denounced his opinions.