Galileo Galilei was born in 1564 in Pisa, Italy and was educated in a monastery. He was interested in mathematics despite his father wanting him to study medicine. Galileo made several important scientific discoveries including using a pendulum to develop the idea for a pendulum clock, proving bodies fall at constant acceleration, and observing the phases of Venus. He improved the telescope and made astronomical observations such as mountains on the Moon and the Milky Way consisting of stars. Galileo supported Copernicus' theory that the Sun is at the center of the solar system and published his findings, for which he was found guilty of heresy by the Catholic Church.