Galileo Galilei's Telescope

        Galileo Galilei was an Italian astronomer, mathematician, philosopher and professor who made pioneering observations of nature with long-lasting implications for the study of physics. He also constructed a telescope and supported the Copernican theory which supports a sun-centered Solar System. Galileo was accused twice of heresy by the church for his beliefs and wrote a number of boks on his ideas.

        In July 1609, Galileo Galilei learned about a simple telescope built by Dutch eyeglass makers and soon developed one of his own. In August, he demonstrated it to some Venetian merchants who saw its value for spotting ships and gave Galileo a salary to manufacture several of them. 

        Galileo’s ambition pushed him to go further, and in the fall of 1609 he made the fateful decision to turn his telescope toward the heavens. Using his telescope to explore the universe, Galileo observed the moon and found Venus had phases like the moon, proving it rotated around the sun, which refuted the Aristotelian  doctrine that the Earth was the center of the universe. He also discovered Jupiter had revolving moons that didn’t revolve around planet Earth. In 1613, he published his observations of sunspots, which also refuted Aristotelian doctrine that the sun was perfect.