Whilst I was out for a walk with my family, I heard a man call his dog Copernicus, which I thought was a very strange name for a dog. When I got home I looked him up and turns out, he is an astronomer!
Before Copernicus, astronomy followed ideas stated by Aristotle. He presented the idea that there were four elements – earth, water, air, and fire. Through this, the point that the Earth was the centre of the universe, and there were 7 planets orbiting, was proposed. He stated that these physical elements moved vertically, based on their gravity. Aristotle positioned the earth as the centre of all, and all motion as uniform, and unchanging. However, observers figured that these objects didn't move like Aristotle proposed. The Earth was not the centre of the orbits and the motion of them were not uniform.
Nicolaus Copernicus (19 February 1473 to 24 May 1543) was a Polish mathematician, astronomer and Catholic canon. He proposed a model of the universe with the Sun at the centre rather than the Earth, which he published in his book 'De Revolutionibus Orbium Coelestium' (On the revolutions of the celestial spheres) in 1953 which led to the Copernican Revolution.
Copernicus was born in Torun, in Royal Prussia in the Crown Kingdom of Poland. He was the youngest of four children of his merchant father. He never married and had no children, but he did have a live-in housekeeper which caused quite a scandal. Copernicus' father died when he was 10 and his paternal uncle Lucas Watzenrode the Younger looked after him and saw to his education; Watzenrode was elected Bishop of Warmia and had connections with leading Polish intellectuals. In 1491-92 Copernicus enrolled in the University of Krakow and began studying in the Department of Arts in the Krakow astronomical-mathematical school. This gave him a thorough grounding in mathematical astronomy and Aristotelian
philosophy.
His learning led to critical analysis of the logical contradictions in the two "official" systems of astronomy of the time - Aristotle's theory of homocentric spheres, and Ptolemy's mechanism of eccentrics and epicycles. In 1497 he was appointed to the Warmia Canonry and in the same year he joined Bologne University where he primarily studied astronomy and the humanities. He became a disciple and assistant to the famous astronomer Domenico Maria Novara da Ferrara. During this time his observations of the occultation of Aldebaran by the moon led to him further questioning Ptolemy's theory of the Moon's motion.
His next excursion was to Padua in 1501 to study medicine. There he also studied Greek and its culture and continued his astronomical observations, before returning to Warmia, where he was based for the rest of his life.
Between 1503 and 1510 Copernicus was his uncle's secretary and physician and, living in the Bishop's castle at Lidzbark, he began his heliocentric theory. This was written into a first outline without all his mathematical 'proof' and was printed in a document known as 'Commentariolus' , which was only available to his closest acquaintances. He purchased and used two residences in the town of Frombork from which he conducted more than half of his over sixty registered astronomical observations.
He was still active in Warmia's chapter and served as its chancellor and visitor of the chapter's estates, as well as administering its economic enterprises as magister pistorae. These did not distract him from his astronomical observations, and he made observations of the Sun in 1515 which led to his discovery of the variability of Earth's eccentricity and the movement of the solar apogee (furthest point from Earth) in relation to the fixed stars.
By 1532, Copernicus had finished his manuscript of 'De Revolutionibus Orbium Coelestium', but did not publish it for fear of derision due to its novelty and incomprehensibility. He relented in 1542, just before he died, and allegedly received the first printed copy on his death bed in 1543. He was buried in Frombork Cathedral.
Copernicus' Heliocentric Theory
Copernicus proposed his model of the Universe where the Earth, planets and stars all revolved around the Sun. He had questioned the classical geocentric model that everything moved around the Earth due to 'corrections' that needed to fit with previous observations of the planets and stars. No true model should need these 'corrections', and his model resolved these mathematical inconsistencies. His model soon gained influential proponents, as it came at a time when European astronomers were struggling with mathematical and observational discrepancies that came out of the then-accepted Ptolemaic geocentric model of the Universe, proposed in the 2nd century CE. Whilst somewhat cumbersome, this model was used for 1500 years.
In 1514 Copernicus had written his Commentariolus briefly outlining his ideas based on seven arguments:
Celestial bodies do not all revolve around a single point
The center of Earth is the center of the lunar sphere - the orbit of the moon around Earth
All the spheres rotate around the sun, which is near the center of the universe
The distance between Earth and the sun is an insignificant fraction of the distance from Earth and sun to the stars, so parallax is not observed in the stars
The stars are immovable – their apparent daily motion is caused by the daily rotation of Earth
Earth is moved in a sphere around the sun, causing the apparent annual migration of the sun. Earth has more than one motion
Earth's orbital motion around the sun causes the seeming reverse in direction of the motions of the planets
In his definitive hypothesis he had multiple observations and calculations to back up his seven principles. His model explained the phases and sine variations of the inferior planets and the retrograde motions of planets like Mars and Jupiter, by explaining that they are significantly closer to Earth when at opposition than when they are at conjunction.
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