50 Fun Facts About Nicolaus Copernicus

Copernicus's model of the universe placed what at its centre instead of the Earth?

A similar heliocentric idea had been proposed by Aristarchus of Samos eighteen centuries earlier, though Copernicus likely arrived at his independently.

What was the title of the 1543 book that presented Copernicus's model?

The title translates as On the Revolutions of the Celestial Spheres.

In which city was Copernicus born on 19 February 1473?

The city sits on the Vistula in what was then Royal Prussia, part of the Crown of the Kingdom of Poland.

What did Copernicus's father, also named Niklas, trade in as a merchant?

He sold it mostly in Danzig and lent money to Poland's king to fight the Teutonic Knights.

Which maternal uncle, later a prince-bishop, took in the orphaned Copernicus?

The Teutonic Order's Grand Master once called him "the devil incarnate".

At which university did Copernicus matriculate with his brother Andrew in winter 1491–92?

It was the heyday of the city's astronomical-mathematical school; his library from those years is held at Uppsala.

Why is Copernicus's astronomy library preserved at Uppsala University in Sweden?

The looting happened during the invasion Poles call the Deluge.

Which star's occultation by the Moon did Copernicus observe with Novara at Bologna on 9 March 1497?

It let him test a peculiarity in Ptolemy's theory of the Moon's motion; the star is the brightest in Taurus.

In which subject did Copernicus receive his doctorate at Ferrara on 31 May 1503?

He had studied medicine at Padua and law at Bologna, but only the law degree was ever formally granted.

Which cathedral chapter made Copernicus a canon in 1497, a post he held for the rest of his life?

It is unclear whether he was ever ordained a priest; he took only the minor orders a canonry required.

Unlike most Renaissance astronomers, what did Copernicus apparently never practise or show interest in?

He must have studied it at Padua, since it was considered part of a medical education.

Which Byzantine historian's 85 short poems did Copernicus translate into Latin and publish in Kraków around 1509?

The moral, pastoral and amorous letters were dedicated to his uncle in gratitude.

What is the short manuscript outline of his heliocentric theory that Copernicus circulated before 1514 called?

It was not printed in full until 1878; Tycho Brahe quoted a fragment in 1602.

In which Baltic cathedral town did Copernicus settle around 1510 and make most of his observations?

He bought the north-western tower of the fortified cathedral hill in 1514 and used a quadrant, triquetrum and armillary sphere.

Roughly how many registered astronomical observations did Copernicus make in his lifetime?

More than half were made at Frombork, using primitive instruments modelled on ancient ones.

What did Copernicus do when Olsztyn was besieged by the Teutonic Knights during the war of 1519–1521?

He then represented the Polish side in the peace negotiations that followed.

Which economic principle, that bad coinage drives out good, did Copernicus formulate in 1526?

He also set down a quantity theory of money in 1517 while advising the Prussian diet on currency reform.

Which pope was so pleased by a 1533 lecture on Copernicus's theory that he rewarded the lecturer?

The lecturer was his secretary Johann Widmanstetter; De revolutionibus was later dedicated to the next pope, Paul III.

Which cardinal wrote from Rome in 1536 entreating Copernicus to publish his "new cosmology"?

The Archbishop of Capua wanted the writings sent "at the earliest possible moment".

Who was the live-in housekeeper whose relationship with Copernicus scandalised two successive bishops?

Bishop Dantiscus banished her from Frombork in spring 1539.

Which Wittenberg mathematician became Copernicus's pupil in 1539 and pushed him to publish?

He wrote the Narratio prima outlining the theory and initially supervised the printing in Nuremberg.

In which city was De revolutionibus printed by Johannes Petreius in 1543?

Copernicus handed the manuscript to his friend Bishop Tiedemann Giese to pass on to Rheticus.

Which Lutheran theologian added an unsigned preface to De revolutionibus calling the theory a mere hypothesis?

He argued the hypotheses "need not be true nor even probable" so long as they matched observations.

According to legend, what happened on the very day Copernicus died, 24 May 1543?

He is said to have woken from a stroke-induced coma, looked at the book, and died peacefully.

Which Protestant reformer sneered at "that Sarmatian astronomer who moves the earth and stops the sun"?

The first attacks on Copernicus came from Protestants, including a Latin comedy that caricatured him as "Morosophus", the Foolish Sage.

What did Erasmus Reinhold publish in 1551 under the sponsorship of Duke Albert?

The Prussian Tables were sponsored by a Protestant duke who had once been Copernicus's military adversary, and quickly replaced their predecessors.

Which ancient Greek astronomer had proposed a Sun-centred system eighteen centuries before Copernicus?

His original text is lost; Archimedes described the idea in The Sand Reckoner.

Roughly how many European astronomers backed Copernicanism 60 years after De revolutionibus?

They included Digges and Harriot in England, Bruno and Galileo in Italy, and Kepler and Maestlin in Germany.

What did Gingerich's 2004 The Book Nobody Read prove about first editions of De revolutionibus?

He examined nearly every surviving copy and demolished Arthur Koestler's claim that nobody had read it.

In which year did the Congregation of the Index suspend Copernicus's De revolutionibus "until corrected"?

The decree came in connection with the Galileo affair, 73 years after the book appeared.

When was the uncensored De revolutionibus finally dropped from the Index of Prohibited Books?

The 1758 Index had already dropped the general ban on heliocentric works, at Roger Boscovich's urging.

What did Copernicus's theory share with that of 14th-century Damascus astronomer Ibn al-Shatir?

He also used the Tusi couple and Urdi lemma from Islamic astronomy, though no route of transmission has been found.

Which Ptolemaic device did Copernicus eliminate, giving his system its simplicity?

He kept perfectly circular orbits, so he still needed epicycles.

Which Renaissance ruler summoned Copernicus to Königsberg in 1541 to treat his sick counsellor?

The former Grand Master of the Teutonic Order had turned his realm Lutheran; the patient recovered in about a month.

When did archaeologists finally locate what they believed to be Copernicus's remains?

Searches in 1802, 1909 and 1939 had all failed; the find was announced in November 2008.

How was the DNA from the rediscovered skeleton matched to Copernicus?

A forensic reconstruction of the skull also showed the broken nose and scar over the left eye seen in his self-portrait.

What was missing from Copernicus's rediscovered skeleton?

He was reburied in the same spot in 2010 under a black granite stone showing a golden Sun circled by six planets.

Which entry on the periodic table was named copernicium in his honour, the name becoming official on his 537th birthday?

Its German discoverers said they deliberately looked worldwide rather than choosing a German name.

Which Danish sculptor designed the Copernicus Monument in Warsaw, completed in 1830?

Jan Matejko's 1873 painting Astronomer Copernicus, or Conversations with God, is the other famous tribute.

What was Copernicus's mother tongue, according to his biography?

He also knew Polish on a par with German and Latin, and historians call the nationality debate a projection of modern ideas onto the Renaissance.

Which Copernican assumption from his early manuscript explains why planets sometimes appear to move backwards?

He argued that Earth's motion alone "suffices to explain so many apparent inequalities in the heavens".

How many "books" or sections was De revolutionibus divided into?

The first gives the general heliocentric vision; the last two treat the planets' motions in longitude and latitude.

At which Italian university did Copernicus study medicine from 1501 to 1503?

The Warmia chapter granted him leave so he could serve as medical adviser to his uncle the bishop; his teachers probably included Girolamo Fracastoro.

In which bishop's castle did Copernicus live as his uncle's secretary and physician from 1503?

It was there that he began work on his heliocentric theory before moving to Frombork around 1510-12.

To which pope did Copernicus dedicate On the Revolutions?

He hoped the dedication would dampen criticism from 'babblers completely ignorant of astronomy'.

What was the title of Copernicus's 1526 treatise on the value of money?

He had advised the Royal Prussian diet on monetary reform for years; the work set out an early form of what became Gresham's law.

At which great church gathering of 1545-1563 was Copernicus's theory conspicuously not discussed?

Publication in 1543 caused only mild controversy, and the Catholic Church took no official action for six decades.

Which Catholic priest sent Galileo a 1616 essay with over twenty arguments against Copernicus?

His objections included the doctrine that hell lies at the centre of the Earth, farthest from heaven.

What did Erasmus Reinhold call his 1551 astronomical compilation based on Copernicus's work?

They were sponsored by the Protestant Duke Albert, who had been Copernicus's military adversary during the Teutonic war.

In which year was Copernicus given a second funeral and reburied in Frombork Cathedral?

The Mass on 22 May 2010 was led by Józef Kowalczyk, the new Primate of Poland; a black granite tombstone names him founder of the heliocentric theory.