How did the heliocentric model of the universe differ from that of Aristotle?
The heliocentric model of the universe promulgated by Nicolaus Copernicus and confirmed by Galileo Galilei differs from that of Aristotle in several ways. In the Aristotelian model, the earth does not move. It sits still at the center of the universe and the "planets" (or wandering stars) move around it in circular orbits. Also, the heavens are unchanging.
In the heliocentric model, the sun is at the center of the solar system and the earth both revolves around the sun and rotates around its own axis. The stars, rather than being affixed to a celestial sphere, are distant objects. Novas and sunspots prove that things outside earth's atmosphere can change.