Nicolaus Copernicus made very few astronomical observations in his lifetime. Yet, he was intelligent enough to spot the inconsistencies in the Ptolemaic model of the universe. His proposed model set the earth in motion and placed the Sun at the center of the universe. This simple and correct insight triggered the modern scientific revolution.
Nicolaus Copernicus (1473-1543) – Astronomer, Economist, Canon
The publication of Copernicus’ De Revolutionibus Orbium Coelestium in 1543 is considered the starting point of modern astronomy. In this book, Copernicus looked beyond the prevailing model of the universe, as described by Aristotle and Ptolemy. The complicated earth-centered model involving epicycles and equants was thrown out in favor of a simpler and elegant model. His proposed model involved uniform circular motion and placed the Sun at the center of the universe. This book, which had been brewing in his mind for close to three decades, might never have been published.
Mikolaj Kopernik (latinized as Nicolaus Copernicus) was born on 19 February 1473 in Thorn, Poland. His father Nicolaus was a successful merchant who traded in copper. His mother Barbara also came from a well-to-do merchant family. When Copernicus was 11 years old, his father died. His uncle Lucas Watzenrode, canon of Frombork, looked after his education and career.
From 1491 to 1495 Copernicus studied at the University of Krakow. Here he became interested in astronomy. He learnt about the Aristotelian and Ptolemaic cosmology and the calculations of horoscopes. To gain a good understanding of the mathematics involved in astronomy, he dabbled in Euclid’s Elements and Regiomontanus’ Tables of Directions. He also bought the recently published Alfonsine Tables to compute the positions of the planets.
Uncle Lucas wanted him to have a career in the Church. Hence, in 1496, Copernicus went to Italy, where he studied canon law at the University of Bologna. At Bologna, his fascination with the heavens continued. He studied Greek, Mathematics, and Astronomy and worked directly under one of the leading astronomers — Domenico Maria Novaro. Copernicus learned to make detailed observations of the sky under his guidance. One of his earliest recorded observation is the Moon eclipsing the star Aldebaran on March 9, 1497.
Even though the Copernican model had shortcomings, his ideas at a higher level introduced a giant leap in our understanding of the universe.
Aristarchus of Samos (310–230 BCE), the Greek astronomer and mathematician, had first presented the idea of the Sun as the center of the universe, with the earth and other planets revolving around it. Copernicus revived this theory. Regiomontanus and Puerbach’s Epitome, a summary of Ptolemy’s Almagest, was published in 1496. Regiomontanus had referred to the oldest Greek texts for the abridged translation. It contains critical notes of discrepancies in Ptolemy’s geocentric model. For example, one important observation was regarding the size of the moon which didn’t vary as much as Ptolemy’s model suggested. Similar inconsistencies would inspire Copernicus to seek a better rationale.
Soon uncle Lucas became the Bishop of Warmia. Through his influence Copernicus was appointed canon of Warmia in 1497, thereby he started earning an income in absentia. He didn’t complete his degree at Bologna. Instead, in 1501, he went to Padua to study Medicine, and eventually, in 1503, he acquired a doctorate in canon law from the University of Ferrara. After completing his education, he joined his uncle in Lidzbark and worked as his secretary. He was also appointed his physician who, being a dignitary of the Church, required constant attention. During this period, he continued to pursue his interests in astronomy.
Copernicus became interested in the Greek language to read texts on Greek astronomy. As part of his learning, he translated into Latin a collection of Greek letters by the poet Theophylactus Simocattes. He published this translation in 1509, dedicating it to his uncle Lucas. Copernicus expressed high regard for the letter collection –
“Theophylactus has disposed so much of value in all of them that they seem to be not letters but rather laws and rules for the conduct of human life.”
This publication marks the first translation of a Greek text in Poland.
In November 1510 Copernicus moved to Frauenburg and took his post as the canon of Warmia. His uncle’s death in 1512 probably allowed him more freedom in pursuing his love of the skies. He soon set up an observatory platform to conduct his observations.
Around 1514 he shared a short 6-page manuscript with his friends describing his ideas. The Little Commentary, as it was known, contained very bold and revolutionary postulates. Apparently, the Sun was standing still relative to the Earth, and it was the Terra Firma that was on move!
Copernicus made the center of the universe near the Sun. He rotated the Earth and other planets around the Sun, and the Moon around the earth. He also rotated the Earth daily around its tilted axis and made the distance of the stars to be far greater in magnitude as compared to other planets. With these postulates, the Copernican model simplified the reasoning behind what we observe from the Earth.
Since olden times, the location of Venus and Mercury relative to the sun wasn’t very clear. Mercury and Venus are visible only around dawn and dusk while other planets are visible anytime at night. In the Copernican model, the orbits of the Mercury and Venus lie within the orbit of the Earth, hence closer to the Sun. This explains the observed phenomenon. Also, the model puts the planets into a proper logical order based on their sidereal periods: Mercury, Venus, Earth, Mars, Jupiter, and Saturn. Copernicus explained the retrograde motion of the planets as an observational effect caused because of the moving earth, and different speed of the orbiting planets. He did not provide any proof for his ideas, reserving it for his larger work.
Although he had formulated the basic tenets of his heliocentric model by 1514, it would take another 29 years for him to have his major work De Revolutionibus published. The delay occurred because of many reasons. Copernicus was a busy man. He had various duties as canon for the cathedral at Frombork. As part of his administrative responsibilities he collected rents from church-owned lands and managed finances. He attended to the bishops of Warmia as a physician. As an expert in economics, he wrote a treatise on currency reforms during the same period. He also contributed to the calendar reform and creation of maps. In 1520, he defended Olsztyn castle against the Teutonic Knights. Probably, the primary reason for the delay was that Copernicus did not want to face the ridicule of the people who couldn’t understand his theory.
“There is talk of a new astrologer who wants to prove that the earth moves and goes around instead of the sky, the sun, the moon, … The fool wants to turn the whole art of astronomy upside-down. However, as Holy Scripture tells us, so did Joshua bid the sun to stand still and not the earth.”– Martin Luther
If not for Georg Rheticus, the Wittenberg mathematician, the manuscript may never have been published.
The young Rheticus traveled from Nuremberg to meet Copernicus. He arrived in Frombork in May 1539 and presented him with many recently published books, including Regiomontanus’ On Triangles of Every Kind. Copernicus allowed Rheticus access to his manuscripts and discussed his theory with him. Rheticus digested most of the work and wrote his introductory summary to the heliocentric theory. The book, titled Narratio Prima (The First Report), provided a fine introduction to the De Revolutionibus. Published in April 1540, it was well received and many requests started coming for Copernicus to publish his full work. Rheticus, along with Copernicus’ canon friend, Tiedemann Giese, finally convinced him to publish his manuscript.
In early 1543, the Nuremberg publisher Johannes Petreius printed the De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres). In the preface, Copernicus dedicated the book to Pope Paul III and explained his motivations for publishing the book. The model based on the moving earth was contrary to the then prevailing ideas. He detested the complexity introduced by eccentrics and epicycles of the Ptolemaic model. They are unnatural and extraneous. He explained that in his model, the movement of all celestial bodies is simple and natural.
“All these facts are disclosed to us by the principle governing the order in which the planets follow one another, and by the harmony of the entire universe, if only we look at the matter, as the saying goes, with both eyes.”– De Revolutionibus
In a twist of the tale, the theologian Andreas Osiander, who was assigned to take care of the publication, added a foreword claiming that the ideas in the book are not the truth, but a mathematical aid to ease calculations – “To the reader… they are not put forward to convince anyone that they are true, but merely to provide a reliable basis for computation”.
Copernicus had communicated with Osiander in July 1540 seeking advice on how to make his book more acceptable when published. Perhaps Andreas Osiander had added the preface accordingly. This downplayed Copernicus’ life’s work.
The publication process of the book coincided with his failing health. Around early December 1542, Copernicus suffered a stroke which paralyzed him. On 24 May 1543, he died of a cerebral hemorrhage. He saw his published work only on the last day of his life.
The book was hardly read immediately after its publication. It was technical and complicated for general readers. With the author’s death, there was nobody to promote the book either. The foreword which misinterpreted the book’s intention was also not encouraging. In the book’s introduction, Copernicus had failed to mention or acknowledge Rheticus. A dejected Rheticus would have nothing more to do with the book. In 1616 the Church found the book’s tenet contrary to the Holy Scripture. On the Revolutions was listed in the Index of Prohibited Books. It would remain there for 200 years until 1835.
Even though the Copernican model had shortcomings, his ideas at a higher level introduced a giant leap in our understanding of the universe. The heliocentric model set the ball rolling for the scientific revolution. In 1600, Johannes Kepler published the Astronomica Nova. Kepler had access to Tycho Brahe’s outstanding collection of observations. He would concur with the heliocentric model and correct the planetary orbits as elliptical instead of circular. Galileo Galilei (1564-1642) and his powerful telescopes observed Jupiter’s moons and phases of Venus. This raised further doubts on the Ptolemaic model. Finally, Isaac Newton (1642-1727) presented the universal gravitational force of attraction to explain the motion of the heavenly bodies.
Further Reading
- Nicholaus Copernicus Minor Works, Edward Rosen, John Hopkins University Press, 1992
- Copernicus’ Secret: How the Scientific Revolution Began, Jack Repcheck, Simon and Schuster, 2008
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- nicolaus-copernicus-heliocentrism-theory-diagram: wikimedia commons | public domain
- nicolaus-copernicus-among-other-astronomers: wellcome collection | CC BY 4.0 International
- nicolaus-copernicus-simple-elegant-revolution: wikimedia commons | public domain
