Explain the significance of the heliocentric theory. What is it? What did it change?

The heliocentric theory is a model in which the Sun lies at the center of the universe and Earth and the other planets revolve around it. This theory was first proposed by Nicolaus Copernicus in 1543. This theory displaced the older theory presented by Ptolemy, which was a geocentric model. This model placed the earth at the center of the universe. Heliocentric theory is viewed as the basis for modern astronomy and the Scientific Revolution.