Answer:
Nicolaus Copernicus proposed the heliocentric model in his work published in 1543, according to NASA Earth Observatory.
Step-by-step explanation:
The heliocentric theory was proposed by Nicolaus Copernicus. He was a Polish astronomer and mathematician who lived in the 16th century. Copernicus suggested that the Sun, rather than the Earth, is at the center of the solar system, and that the planets, including Earth, orbit around the Sun.
Copernicus' heliocentric theory challenged the prevailing belief at the time, which was the geocentric theory. According to the geocentric theory, the Earth was considered to be the center of the universe, with all celestial bodies revolving around it. Copernicus' theory revolutionized our understanding of the universe and laid the foundation for modern astronomy.
Copernicus' heliocentric theory was further supported by observations made by other astronomers, such as Johannes Kepler and Galileo Galilei, who provided evidence through their observations and calculations.
In conclusion, Nicolaus Copernicus proposed the heliocentric theory, which states that the Sun is at the center of the solar system, and the planets, including Earth, orbit around it.