Copernicus believed that the planets in the solar system revolved around the sun, instead of believing that the Earth was the center of the solar system. His model included the position of the Earth and retrograde revolutions.
Copernicus also theorized that the Earth was on a tilted axis that moved in an orbit. He also postulated on the role of the moon in observing the occultation of the star Aldebaran by the moon. His work made it possible to use mathematical equations to discover the solar system. Galileo later expanded Copernicus' work to create the modern version of the universe using a telescope instead of the naked eye.