Physics Preliminary Assessment Assignment 1Christos Toras MODELS OF THE UNIVERSE - CHRONOLOGY From the time of Aristotle until the time of Newton there were five models of what humans thought of 'universe. The astronomers who developed these models were Aristotle, Ptolemy, Copernicus, Tycho Brahe, Kepler, Galileo and Newton. Aristotle's model of the universe was a geocentric universe. This meant that the Earth was at the center of the universe and that all the stars were located on one celestial sphere. A celestial sphere is an imaginary sphere that serves as a dome around the Earth from which you can see the stars and the universe. Although Aristotle's model was valid for its time, it failed to explain the retrograde motion of the planets. Retrograde motion is Ptolemy's model of the universe was still geocentric but included epicycles to explain retrograde motion which Aristotle's model could not explain. Ptolemy was able to determine that not only did the planets orbit the sun on a deferent, but they also orbited on what he called an epicycle n. Copernicus' model was heliocentric, placing the sun stationary at the center and also had everything rotating. around it in a circle. He developed his model in secret so as not to anger the church. Before he died in 1543 he published his ideas and, as expected, his ideas were labeled as sins against the church. During the 1500s, however, Danish astronomer Tycho Brahe meticulously studied and charted the night sky with great precision. Since telescopes had not yet been invented, he developed his own instruments for measuring astronomy. His methods were so detailed and had an accuracy of 0.5 arc minute. His model was a combination of geocentric and hell… middle of paper… the Olympian Gods created everything, including the universe, and therefore the creation of the Universe had no explanation. In the article by Surendra Singh, Ph.D., Professor of Biology, et al argue that “In ancient times, nature was explained as the actions of the gods. Early Greek philosophers questioned the role of the gods as the cause of events as early as the 5th century BC.” This shows that the religion of the time greatly influenced Aristotle's model. In conclusion, there are many technological advancements in the 21st century. After Aristitle and the other astronomers, many technological advances were made, such as the use of the telescope to be able to see further into the known universe. Aristotle's model of the universe created a solid foundation of the universe for other astronomers to create their own models.