Jenni Lambe

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.