Editing Galilean moons (section)

=== Names ===
[[File:Sidereus Nuncius Medicean Stars.jpg|thumb|right|upright|The Medician stars in the ''[[Sidereus Nuncius]]'' (the 'starry messenger'), 1610. The moons are drawn in changing positions.]]
[[File:Apparatus to demonstrate the motion of Jupiter's satellites in Putnam Gallery, 2009-11-24.jpg|thumb|A ''[[Jovilabe]]'':<ref>{{cite web | url=https://catalogue.museogalileo.it/object/Jovilabe.html | title=Jovilabe | publisher=[[Museo Galileo]] | access-date=15 April 2015 | url-status=live | archive-url=https://archive.wikiwix.com/cache/20150416155028/https://catalogue.museogalileo.it/object/Jovilabe.html | archive-date=16 April 2015 }}</ref> an apparatus from the mid-18th century for demonstrating the orbits of Jupiter's satellites]]

In 1605, Galileo had been employed as a mathematics tutor for [[Cosimo II de' Medici, Grand Duke of Tuscany|Cosimo de' Medici]]. In 1609, Cosimo became Grand Duke Cosimo II of [[Tuscany]]. Galileo, seeking patronage from his now-wealthy former student and his powerful family, used the discovery of Jupiter's moons to gain it.<ref name=Galileo89/> On 13 February 1610, Galileo wrote to the Grand Duke's secretary:<ref name=Galileo89/>

{{blockquote|God graced me with being able, through such a singular sign, to reveal to my Lord my devotion and the desire I have that his glorious name live as equal among the stars, and since it is up to me, the first discoverer, to name these new planets, I wish, in imitation of the great sages who placed the most excellent heroes of that age among the stars, to inscribe these with the name of the Most Serene Grand Duke.}}

Galileo initially called his discovery the '''Cosmica Sidera''' ("Cosimo's stars"), in honour of Cosimo alone.{{Efn|''[[wikt:Cosimo|Cosimo]]'' is the Italian form of the Greek name ''[[wikt:Cosmas|Cosmas]]'' itself deriving from ''[[wikt:κόσμος#Ancient Greek|cosmos]]'' (whence the [[Grammatical gender|neuter]] plural adjective ''cosmica''). ''Sidera'' is the plural form of the Latin noun ''[[wikt:sidus#Latin|sidus]]'' "star, constellation".}} Cosimo's secretary suggested to change the name to '''Medicea Sidera''' ("the '''Medician stars'''"), honouring all four Medici brothers (Cosimo, Francesco, [[Carlo de' Medici (cardinal)|Carlo]], and Lorenzo).<ref name=Galileo89/> The discovery was announced in the ''[[Sidereus Nuncius]]'' ("Starry Messenger"), published in [[Venice]] in March 1610, less than two months after the first observations.

On 12 March 1610, Galileo wrote his dedicatory letter to the Duke of Tuscany, and the next day sent a copy to the Grand Duke, hoping to obtain the Grand Duke's support as quickly as possible. On 19 March, he sent the telescope he had used to first view Jupiter's moons to the Grand Duke, along with an official copy of ''[[Sidereus Nuncius]]'' (''The Starry Messenger'') that, following the secretary's advice, named the four moons the Medician Stars.<ref name=Galileo89/> In his dedicatory introduction, Galileo wrote:<ref name=Galileo89/>

{{blockquote|Scarcely have the immortal graces of your soul begun to shine forth on earth than bright stars offer themselves in the heavens which, like tongues, will speak of and celebrate your most excellent virtues for all time. Behold, therefore, four stars reserved for your illustrious name{{nbsp}}... which{{nbsp}}... make their journeys and orbits with a marvelous speed around the star of Jupiter{{nbsp}}... like children of the same family{{nbsp}}... Indeed, it appears the Maker of the Stars himself, by clear arguments, admonished me to call these new planets by the illustrious name of Your Highness before all others.}}

Other names put forward include:
* I. ''Principharus'' (for the "prince" of Tuscany), II. ''Victripharus'' (after [[Vittoria della Rovere]]), III. ''Cosmipharus'' (after [[Cosimo I de' Medici, Grand Duke of Tuscany|Cosimo de' Medici]]) and IV. ''Fernipharus'' (after Duke [[Ferdinando II de' Medici, Grand Duke of Tuscany|Ferdinando de' Medici]])<ref>{{cite book|title=Annuaire de l'Observatoire royal de Bruxelles|url=https://books.google.com/books?id=eF4LAQAAIAAJ&pg=PA263|year=1879|publisher=L'Académie royale des sciences, des lettres et des beaux-arts de Belgique|page=263|access-date=2016-03-03|archive-date=2016-04-29|archive-url=https://web.archive.org/web/20160429062938/https://books.google.com/books?id=eF4LAQAAIAAJ&pg=PA263|url-status=live}}</ref> – by [[Giovanni Battista Hodierna]], a disciple of Galileo and author of the first [[Ephemeris|ephemerides]] (''Medicaeorum Ephemerides'', 1656);
* ''Circulatores Jovis'', or ''Jovis Comites'' – by [[Johannes Hevelius]];
* ''Gardes'', or ''Satellites'' (from the Latin ''satelles, satellitis'', meaning "escorts") – by [[Jacques Ozanam]].

The names that eventually prevailed were chosen by [[Simon Marius]], who discovered the moons independently at the same time as Galileo: he named them at the suggestion of [[Johannes Kepler]] after lovers of the god Zeus (the Greek equivalent of Jupiter), in his ''Mundus Jovialis'', published in 1614:<ref name=Helden>{{cite journal |last1=Van Helden |first1=Albert |title=Naming the Satellites of Jupiter and Saturn |journal=The Newsletter of the Historical Astronomy Division of the American Astronomical Society |date=August 1994 |issue=32 |url=https://had.aas.org/sites/had.aas.org/files/HADN32.pdf |access-date=10 March 2023}}</ref>

{{blockquote|Jupiter is much blamed by the poets on account of his irregular loves. Three maidens are especially mentioned as having been clandestinely courted by Jupiter with success. Io, daughter of the River Inachus, Callisto of Lycaon, Europa of Agenor. Then there was Ganymede, the handsome son of King Tros, whom Jupiter, having taken the form of an eagle, transported to heaven on his back, as poets fabulously tell{{nbsp}}... I think, therefore, that I shall not have done amiss if the First is called by me Io, the Second Europa, the Third, on account of its majesty of light, Ganymede, the Fourth Callisto{{nbsp}}... This fancy, and the particular names given, were suggested to me by Kepler, Imperial Astronomer, when we met at Ratisbon fair in October 1613. So if, as a jest, and in memory of our friendship then begun, I hail him as joint father of these four stars, again I shall not be doing wrong.}}

Galileo steadfastly refused to use Marius' names and invented as a result the numbering scheme that is still used nowadays, in parallel with proper moon names. The numbers run from Jupiter outward, thus I, II, III and IV for Io, Europa, Ganymede, and Callisto respectively.<ref name="marazzini"/> Galileo used this system in his notebooks but never actually published it.<ref name=Helden/> The numbered names (Jupiter ''x'') were used until the mid-20th century when other inner moons were discovered, and Marius' names became widely used.<ref name="marazzini">{{cite journal|last=Marazzini|first= C.|date=2005|title=The names of the satellites of Jupiter: from Galileo to Simon Marius|journal=Lettere Italiana|volume=57|issue= 3|pages=391–407}}</ref>

<gallery caption="The Galilean moons' namesakes">
File:Io Argos MAN Napoli Inv9556.jpg|Io (left) watched by [[Argus Panoptes]] (right) on Hera's orders
File:Wall painting - Europa and the bull - Pompeii (IX 5 18-21) - Napoli MAN 111475 - 02.jpg|Europa on the back of Zeus turned into a bull
File:Zeus abducts Ganymede, large terracotta, before 470 BC, AM Olympia, Olym26.jpg|Ganymede (left) abducted by Zeus (right)
File:Wall painting - Artemis and Kallisto - Pompeii (VII 12 26) - Napoli MAN 111441.jpg|Callisto (leftmost) with Eros and other nymphs, with Artemis seated
</gallery>