The theory that states the Sun is the center of the universe and planets revolve around it is called the heliocentric model.

It was first proposed by Nicolaus Copernicus in the 16th century, challenging the prevailing geocentric model which placed the Earth at the center of the universe.

While not entirely accurate in the modern understanding of the universe (as the Sun is just one star among many in the Milky Way galaxy), the heliocentric model was a significant advancement in our understanding of the solar system and laid the foundation for modern astronomy.