During the Middle Ages much of the knowledge of the ancient world was forgotten or lost. The main idea of the universe during the middle ages was the idea of the geocentric universe. Aristotle's system of the earth centered universe agreed with the doctrine of the Catholic Church in many ways. The Church also accepted Aristotles's idea that the living things on earth stay the same for all times. Dante wrote a book about astronomy during the middle ages, based mostly on the ideas of Ptolemy and Aristotle. He believed the physical objects behaved more like living things. For example he thought objects aspired to reach the center of the earth. Religious ideas affected scientific ideas during the Middle Ages
In Arabia, advances were made during that time period. They were able to calculate eclipses. The mathematician al-Khwarizami came up with astronomical tables which told the times of the phases of the moon, sunrise and sunset, and also the rising and setting of the planets.
With the Renaissance, ideas of astronomy began to change. Nicolaus Copernicus presented the idea of the heliocentric (sun centered) universe. Copernicus delayed the publishing of his book until he was nearly on his death bed, since he know the church would not like his ideas. He was right. His idea was not accepted by the churches and they banned his book, along with others promoting the sun centered universe. Some people were punished or excommunicated for promoting the heliocentric theory.
Johannes Kepler changed the idea planets moved in circles. He found out Mars had an elliptical orbit. Kepler wrote several laws of planetary motion. People began to wonder WHY the planets moved.
The telescope was invented in 1609 allowing new advances in astronomy. Galileo used his findings to point out the errors in the geocentric system to a larger amount of people than Copernicus. The Catholic church, which had warned Galileo not to promote the heliocentric system, banned his book. In 1633 he was brought to Rome and placed under house arrest for the rest of his life. By that time, however, the 'cat was out of the bag' and people were questioning the geocentric system.
Another interesting development during the Renaissance was an adjustment to our current calendar. It was know as the Gregorian adjustment, since it was doen by Pope Gregory. The calendar that we use today is descended from the Roman calendar made by Julius Caesar. There was an error in astronomical calculation of the calendar however (they didn't realize the year wasn't exactly 365.25 days, but a little bit shorter). By 1582 the calendar was over ten days off, and the equinoxes were coming ten days early. Pope Gregory made an adjustment to the calendar, since they now realized that only century years divisible by four should have leap years. The Pope also skipped enough days to match the calendar back up. Protestant countries didn't accept the Pope's decree, so they didn't end up changing their calendars until 1752!
Sir Isaac Newton helped to conclude the time of change. He found the correct laws of motion and gravity, which is what causes the planets to move. Newton wrote his book in Latin, and it was complex, but many "popular" versions of his book were made. Newton's theories were more widely accepted since by the 18th century people felt more things could be explained by science and reason.