Final answer:
The replacement of the geocentric model with the heliocentric model is an example of a paradigm shift, indicating a significant change in the foundational principles of astronomy.
Step-by-step explanation:
When the theory that Earth is the center of the universe was replaced with the understanding that Earth orbits the Sun, this was an example of a paradigm shift. A paradigm shift occurs when a fundamental change happens in the basic concepts or experimental practices of a scientific discipline. Ancient models that placed Earth at the center, developed through astronomical observation, were challenged as more scientific discoveries occurred via improved observational methods. Aristarchus of Samos proposed that Earth moved around the sun, which greatly deviated from the prevailing Aristotelian views. However, it was not until the work of figures like Copernicus, Kepler, and Galileo that the heliocentric model became widely accepted.