contributions to astronomy

             Fifteen forty-three can be considered the first year of modern science. This year Nicholaus Copernicus published De revolutionibus orbium coelestium (Cohen, I. 24). The old physics of Aristotle and the astronomy of Ptolemy were countered by Copernicus. Many of Copernicus" ideas of astronomy, mainly his heliocentric view, which was actually proposed first by the Greek philosopher Aristarchus, were already made known in literature. However, the ideas of Aristarchus were lost with the rise of Aristotelian physics almost 2000 years previous to Copernicus" revisions and publication of the heliocentric idea (Cohen, I. 25). Although Copernicus" views on astronomy were made public in his book the year of his death, the geocentric view of the heavens did not give way to the heliocentric view. Only until Galileo and Kepler did heliocentric view of the universe become prominent. .
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             Around 1514 Copernicus distributed a little book, not printed but hand written, to a few of his friends who knew that he was the author even though no author is named on the title page. This book, usually called the Little Commentary, set out Copernicus's theory of a universe with the sun at its center. It contained seven axioms which Copernicus gives (Copernicus). "There is no one center in the universe. The Earth's center is not the center of the universe. The center of the universe is near the sun. The distance from the Earth to the sun is imperceptible compared with the distance to the stars. The rotation of the Earth accounts for the apparent daily rotation of the stars. The apparent annual cycle of movements of the sun is caused by the Earth revolving round it. The apparent retrograde motion of the planets is caused by the motion of the Earth from which one observes.".
             The seventh axiom would be the most profound of these statements. "Although earlier scholars had claimed that the Earth moved, some claiming that it revolved round the sun, nobody before Copernicus appears to have correctly explained the retrograde motion of the outer planets (Copernicus).