In 1543, a model of the solar system was published that put the Sun in the center of the solar system, and demoted Earth to just another planet. This model was proposed by which astronomer?

The model of the solar system that placed the Sun at the center, known as the heliocentric model, was proposed by the astronomer Nicolaus Copernicus. His work, titled "De revolutionibus orbium coelestium" (On the Revolutions of the Celestial Spheres), was published in 1543 and fundamentally changed the way we understand our place in the universe.