Which astronomer proposed a heliocentric model of the universe?

The proposed heliocentric model of the universe, which places the Sun at the center rather than the Earth, is attributed to Copernicus. His work fundamentally changed the scientific view of the cosmos in the 16th century, contradicting the long-held geocentric model that placed Earth at the center. Copernicus's ideas laid the groundwork for future astronomers and contributed significantly to the Scientific Revolution, influencing the development of modern astronomy.

Galileo supported and advanced the heliocentric model through his observations of celestial bodies, but he did not originate the concept. Isaac Newton made significant contributions to our understanding of gravity and motion, enhancing the scientific basis of Copernican theory, but he did not propose the heliocentric model itself. Niels Bohr worked primarily in the field of quantum mechanics and atomic structure, which falls outside the realm of this particular astronomical debate.