Which astronomers proposed the heliocentric model?

• A. Copernicus and Galileo
• B. Aristotle
• C. Ptolemy
• D. Newton

Answer: (C)

The Sun-centered arrangement, where planets orbit the Sun, was first proposed by Nicolaus Copernicus. He challenged the long-standing belief that Earth was at the center of the universe and laid out a model in which the planets—including Earth—move around the Sun. Before him, Ptolemy defended a geocentric system with Earth at the center and complex epicycles to explain motions. Aristotle supported the older geocentric views, while Newton later provided the gravitational framework that explains why orbits occur, but did not originate the heliocentric idea. Galileo’s telescopic observations later offered strong evidence, reinforcing Copernicus’s model.