As a university-trained Catholic priest dedicated to astronomy,
Copernicus was acquainted with the Sun-centered cosmos of the ancient Greek
Aristarchus.
Although he circulated an outline of the heliocentric theory to colleagues decades earlier, the idea was largely forgotten until late in his life he was urged by a pupil to complete and publish a mathematically detailed account of his model. Copernicus's challenge was to present a practical alternative to the Ptolemaic model by more elegantly and accurately determining the length of a solar year while preserving the
metaphysical implications of a mathematically ordered cosmos. Thus his heliocentric model retained several of the Ptolemaic elements causing the inaccuracies, such as the planets' circular orbits, epicycles, and uniform speeds, while at the same time re-introducing such innovations as:
-Earth is one of seven ordered planets in a solar system circling a stationary Sun
-Earth has three motions: daily rotation, annual revolution, and annual tilting of its axis
-Retrograde motion of the planets is explained by Earth's motion
-Distance from Earth to the Sun is small compared to the distance to the stars.
The Copernican system did not offer better predictions than the geocentric system, and it posed problems for both natural philosophy and scripture. The Copernican system was no more accurate than Ptolemy's system, because it still used circular orbits. This was not altered until Johannes Kepler postulated that they were elliptical (Kepler's first law of planetary motion).
Geocentric model of Aristotle and Ptolemy... A change in a parameter to improve the fit in one place would throw off the fit somewhere else. Ptolemy's model is probably optimal in this regard. On the whole it gave good results but missed a little here and there. Experienced astronomers would have recognized these shortcomings and allowed for them.
Giordano Bruno (1548 – February 17, 1600), born Filippo Bruno, was an Italian Dominican friar, philosopher, mathematician and astronomer. His cosmological theories went beyond the Copernican model in proposing that the Sun was essentially a star, and moreover, that the universe contained an infinite number of inhabited worlds populated by other intelligent beings. In addition to his cosmological writings, Bruno also wrote extensively on the art of memory, a loosely organized group of mnemonic techniques and principles. . Bruno's feats of memory were based, at least in part, on his elaborate system of mnemonics, but some of his contemporaries found it easier to attribute them to magical powers. Given that Bruno dedicated various works to the likes of King Henry III, Sir Philip Sidney, Michel de Castelnau (French Ambassador to England), and possibly Pope Pius V, it is apparent that this wanderer had experienced a meteoric rise and moved in powerful circles.
Moreover, his 120 theses against Aristotelian natural science and his pamphlets against the mathematician Fabrizio Mordente soon put him in ill favor. In Germany he failed to obtain a teaching position at Marburg, but was granted permission to teach at Wittenberg, where he lectured on Aristotle for two years. However, with a change of intellectual climate there, he was no longer welcome, and went in 1588 to Prague, where he obtained 300 taler from Rudolf II, but no teaching position. He went on to serve briefly as a professor in Helmstedt, but had to flee again when he was excommunicated by the Lutherans. During this period he produced several Latin works, dictated to his friend and secretary Girolamo Besler, including De Magia (On Magic), Theses De Magia (Theses On Magic) and De Vinculis In Genere (A General Account of Bonding). He went to Padua, where he taught briefly, and applied unsuccessfully for the chair of mathematics, which was assigned instead to Galileo Galilei one year later.... Bruno's cosmology is marked by infinitude, homogeneity, and isotropy, with planetary systems distributed evenly throughout. Matter follows an active animistic principle: it is intelligent and discontinuous in structure, made up of discrete atoms.
Some authors have characterized Bruno as a "martyr of science," suggesting parallels with the Galileo affair which began around 1610. They assert that, even though Bruno's theological beliefs were an important factor in his heresy trial, his Copernicanism and cosmological beliefs also played a significant role for the outcome.
Gregory XIII (7 January 1502 – 10 April 1585), born Ugo Boncompagni, was Pope from 1572 to 1585. He is best known for commissioning and being the namesake for the Gregorian calendar, which remains the internationally accepted civil calendar to this date. The reason for the reform was that the average length of the year in the Julian calendar was too long – it treated each year as 365 days, 6 hours in length, whereas calculations showed that the actual mean length of a year is slightly less (365 days, 5 hours and 49 minutes) As a result, the date of the actual vernal equinox had slowly (over the course of 13 centuries) slipped to 10 March, while the computus (calculation) of the date of Easter still followed the traditional date of 21 March.
The
Alfonsine tables provided data for computing the position of the Sun, Moon and planets relative to the fixed stars. The tables were named after Alfonso X of Castile, who sponsored their creation, they were compiled in Toledo, Spain. They contain astronomical data starting on January 1, 1252, the date of the coronation of the King.
The Alfonsine tables were the most popular astronomical tables in Europe and updated versions were regularly produced for three hundred years. Copernicus himself owned a copy. In 1551, the Prutenic Tables (or Prussian Tables) of Erasmus Reinhold's were published . These tables used the Copernican heliocentric model of the solar system. Copernicus's publication, De revolutionibus, was not easy to use and the
Prutenic tables were intended to make the heliocentric model more usable by astrologers and astronomers. However, the Prutenic tables were not widely adopted outside German speaking countries and new ephemerides based on the Alfonsine tables continued to be published[8] until the publication of
Johannes Kepler's
Rudolphine Tables in 1627.
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