Before Nicolaus Copernicus shared his view of the solar system, the general belief was that all the heavenly bodies revolved around the Earth. Copernicus transformed the study of astronomy when he proposed that our solar system was not geocentric, but heliocentric -- that the planets revolved around the sun.
Nicolaus Copernicus was born in Torun, Poland, on Feb. 19, 1473, to a wealthy family. He was the youngest of four children. His father died when he was about 10 years old, leading him to live with his uncle Lucas Waltzenrode. Under his uncle's guidance, Copernicus studied astronomy and astrology at the University of Cracow and then law at the University of Bologna in Italy.
Copernicus began studying medicine at the University of Padua. The study of medicine in the 1500s was related to astrology because it was thought that the stars affected the body. He eventually received his doctorate from the University of Ferrara. He returned to Poland to begin employment as a church canon, which means he had financial, military and medical responsibilities. In his spare time, he used his extensive education to develop his theory of a heliocentric (sun-centred) solar system.
Early Theory of Astronomy
Aristotle, an ancient Greek philosopher, formed the first theory of astronomy. In this theory, the Earth was central and the sun and planets (the seven that were identified at the time) revolved around it. According to Aristotle, the stars were fixed in arrangement, all revolving around the Earth as a unit. Copernicus' study of mathematics showed him that this theory could not have been true. For as many times as he tried, Copernicus could not make his calculations match Aristotle's theory. This made him doubt the geocentric theory's validity, and Copernicus began to form his own theory of the Earth's position in the solar system.
Copernicus was not the only person who theorised that the sun was the centre of our solar system. Followers of the Greek philosopher Pythagoras suspected that Earth was not the centre, and according to writings of Archimedes, Aristarchus of Samos had hypothesised a heliocentric model of the solar system. With these writings and those of learnt Islamic astronomic study, Copernicus developed his own heliocentric theory. According to legend, Copernicus was presented with his published work, "On the Revolutions," which outlined this heliocentric theory, on his deathbed, on May 24, 1543.