Copernicus has been named one of the most influential people this millennia by Time Magazine; in part for his movements in though during the scientific revolution; creating a basis for modern astronomy and challenging the Church (of the 15th century) to lead the way to a reform in thinking. He did so by disproving (mathematically) a theory of the heavens that had existed for almost 14 centuries, established by a man named Charles Ptolemy in 250 AD. Copernicus revolutionized astronomy by creating a solid basis for it to stand on, discovering that "The Earth was not the centre of the cosmos, but rather one celestial body among many, as it became subject to mathematical description." He compiled a manuscript of his theories, including the retrogressive behaviour of the planets, cause by the Earth's daily rotation on its axis and yearly revolution around the sun. Much of Copernicus' influence was rooted in the minds of men for years, perhaps because his theories were not fully understood or appreciated until many years after his death in 1543. Finally, Nicolaus Copernicus had a theory published (anonymously) that went against Catholic Church authority, a very bold step for someone in that era. The Church relented, and allowed the circulation of the manuscript.
The Ptolemic System, up until the 1510s was the only way of thinking about the solar system as they knew it. The Church firmly believed the Earth was the centre of the universe, and as far as the community in that era was concerned, the Church's way of thinking was the correct way of thinking. For a great many years, the Ptolemic System had ruled the minds of astronomers; the Earth was the centre of the universe, and that Mercury, Venus, our Moon, Mars, Jupiter, Saturn, and the Sun all revolved around the Earth. As Copernicus recorded the movements of Mars, he noticed a peculiar pattern in its movements. Every night, its position differed slightly, mostly travelling west, then for a few days east again, then continuing west. He called the phenomenon retrograde motion, and it seemed to explain a rotation of the Earth. During his years as a student in universities (1491-1503), he found the first defects in the Ptolemic System, and after much concentration, he developed a manuscript with his theories of the Heaven in 1514, De revoltionibus orbium coelestium, libri (English Translation: On the Revolutions of the Celestial Spheres). With this, he anonymously circulated his ideas among his close friends, and gained quite a following. Any students who had heard his lectures or read his theories were immediately fascinated and learned to follow his research.
Copernicus wrote De revoltionibus in six sections, as a mathematical reinterpretation of the Ptolemaic System. In the first section, he gave some basic mathematical rules, countering old arguments about the fixity of the Earth, and discussed the order of the planets from the sun. He could no longer accept the old arrangement - Earth, Moon, Mercury, Venus, Sun, Mars, Jupiter, and Saturn - since this had been a consequence of a geocentric system. He found it necessary to adapt it to his heliocentric system and adopted the following order from the stationary Sun: Mercury, Venus, Earth with the Moon orbiting around it, Mars, Jupiter, and Saturn.
Not only was Copernicus correct in his theories, but many of his observations and notions about the functions of our heavens still hold true today.
The Copernican theory demanded two important changes in outlook. The first had to with the apparent size of the universe. The stars always appeared fixed in precisely the same position, but if the Earth orbited around the Sun, they should display a small periodic change. Copernicus explained that the star was far too distant for the change to be detected. His theory thus led to the belief in a much larger universe than previously conceived and, in England, where the theory was openly accepted with enthusiasm, to the idea of an infinite universe with the stars scattered throughout space. The second change concerned the reason why bodies fall the ground. Aristotle has taught that they fall into their "natural place," which was the centre of the universe.
However, because according to the heliocentric theory, the Earth no longer coincided with the centre of the universe, a new explanation was needed. This re-examination of the laws governing falling bodies eventually led to the Newtonian concept of universal gravitation.
The dethronement of the Earth from the centre of the universe caused profound shock. No longer could the Earth be considered the epitome of creation, for it was only a planet like other planets. The successful challenge to the entire system of ancient authority required a complete change in man's philosophical conception of the universe. This is what's rightly termed "the Copernican Revolution."
The reluctance of the Church to accept any new theories indicated it's long stronghold over the minds of people in science. People feared change, for the consequence for an upset with the Church was never certain, but its outlook was never good. Without the approval of the Church, no progress could be made in the development of mankind. Martin Luther was one of Copernicus' biggest challenges to overcome, trying to prevent Copernicus from giving lectures and teaching his students at local universities. But, when Luther himself admitted, "It was Joshua who told the Sun, not the Earth to stand still," it showed the world what one man could accomplish. His success overcoming the Church administrators was partly due to his own influences within the Church. He held many positions in the Church and had attained Canon by the time of his death. Being able to explain to the Church in it's own words using The Bible as example (see footnote 2), is the suspected theory for his success.
"The major premises of Copernicus's theory are that the earth rotates daily on its axis and revolves yearly around the sun." Copernicus' heliocentric theories of planetary motion had the advantage of accounting for the apparent daily and yearly motion of the sun and stars. It neatly explained the apparent retrograde motion of Mars, Jupiter, and Saturn and the fact that Mercury and Venus never move more than a certain distance from the sun. Copernicus's theory also stated that the sphere of the fixed stars was stationary. In Copernicus's universe, unlike that of Ptolemy, the greater the radius of a planet's orbit, the greater the time the planet takes to make one circuit around the sun. But the price of accepting the concept of a moving earth was too high for most 16th-century readers who understood Copernicus's claims. In addition, Copernicus's calculations of astronomical positions were neither decisively simpler nor more accurate than those of his predecessors, even though his theory made good physical sense, for the first time, of planetary movements.
The publication of his manuscript was not his idea, despite his wanting to publish it, he never did. The manuscript is said to have been completed and circulated in the 1530s, while Copernicus continued his studies. It wasn't until his pupil Rheticus convinced him to publish it 10 years later did it actually make it to print, it is said that Copernicus was on his deathbed when he received a copy of his masterpiece. Many people studied the manuscript and used it as their own guide to success. Famous historians have said, "Copernicus conceived his theory in an epoch which was intellectually not yet ready to accept it, nor was science ready to accept it." Copernican followers include: Thomas Smith (a mathematician possessed a copy of De Revolutionibus in his library), and his pupil Robert Recorde became the first protagonist of the Copernican theories. Great philosopher Thomas Hobbes acknowledged that all enlightened men of his time shared views of Copernicus on the world structure and maintained that Copernicus achieved much more than he himself thought. The heliocentric system became taught at schools such as Oxford, Sorbonne, and Yale after the manuscripts release from Catholic Church hold in the 1820s.
The Church became afraid of too much change, and 'repossessed' any copies of De Revolutionibus still circulating in the 1600s.
Copernicus gave way to many astronomers, not only in his home of Poland, but to those of his dear friends in Italy with whom a lot of revolution was happening. Old notions were being questioned in Italy, and many new theories were being constructed. The expansion in thinking gave way for astronomers like Johannes Kepler and Galileo Galilei who further revolutionized astronomy as we know it today.
Nicolaus Copernicus, born Mikolaj Kopernik, of Thorn, Poland accomplished a great many things, some we take for granted. He created an infinite number of possibilities of directions for astronomy to take. He expanded the minds of humans everywhere, and especially those of the Catholic Church. His manuscript De Revolutionibus created quite a stir, and raised a following among the students he lectured infrequently. "Considered the father of modern astronomy, he completely revolutionized science in the 1500s, giving way to others with radical theories to present them, and be accepted, not rejected." By the time of Copernicus' passing, most of Europe was thirsting for more information. What he contributed to astronomy will not be forgotten, and many new ideas shall rise because of his radical thinking, making him truly worthy of being 'The father of Modern Astronomy," and being placed on Time Magazine's list of the 100 most influential people of the millenia.