According to the NASA, Nicolaus Copernicus developed the heliocentric theory of astronomy and determined that Earth rotates on its axis. Born in 1473, Copernicus is known as the father of astronomy, paving the way for other astronomers, such as Galileo, to make later advancements.
According to NASA, Nicolaus Copernicus is most famous for the heliocentric, also known as sun-centered, theory of astronomy. The heliocentric theory is the theory that the planets orbit around the sun. Before Copernicus, the main scientific belief was Ptolemy's geocentric theory, which stated that Earth was the center of the universe and that the sun and planets revolved around it. Because his theory directly opposed what the majority of people believed, Copernicus faced a great deal of opposition from both the Catholic Church and the scientific community of the 15th century.
Because Copernicus did not have access to a telescope and was forced to observe the sky with the naked eye, he could not prove the heliocentric theory and died in 1543 before it was proven correct. By the 17th century, however, future astronomers, such as Galileo, were able to prove Copernicus' geocentric theory as correct by using both observations from telescopes and breakthroughs in physics.