How did Nicolaus Copernicus’s heliocentric model differ from Ptolemy’s geocentric system?

The primary difference between the two models lies in the placement of the Earth and the Sun within the solar system.

• Ptolemaic System: This geocentric model, formulated by Ptolemy, assumes that a stationary Earth is the center of the universe. To account for the observed irregular movements of planets, it utilizes a complex system of epicycles and deferents, as well as an equant point to maintain the appearance of uniform circular motion.123
• Copernican System: Proposed by Nicolaus Copernicus, this heliocentric model places the Sun at the center. It posits that Earth is a planet that orbits the Sun annually and rotates daily on its own axis.45

While Copernicus’s model offered a more harmonious and qualitatively simpler system, he still retained some of the traditional apparatus of epicycles and deferents to achieve predictive accuracy. Ultimately, Copernicus shifted the paradigm by asserting that astronomy must describe the real, physical system of the world rather than serving merely as a mathematical tool.42