Galileo didn`t discover the telescope, but he improved it. In 1609, Galileo learned about the device and developed one of his own, significantly improving its design. That fall, he pointed it at the moon and discovered it had craters and mountains, debunking the common belief that the moon’s surface was smooth. Galileo soon went on to make other findings with his telescope, including that there were four moons orbiting Jupiter and that Venus went through a complete set of phases (indicating the planet traveled around the sun). Galileo’s discoveries brought him acclaim and in 1610 he was named the chief mathematician and philosopher to the grand duke of Tuscany as well as chief mathematician at the University of Pisa. More significantly, Galileo’s observations would lead him to support the theory, laid out in 1543 by Polish mathematician and astronomer Nicolaus Copernicus, that the sun is the center of the universe and the Earth and other planets revolve around it.
