EDWARD'S LECTURE NOTES:
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C O U R S E
Moons of Our Solar System
David Rothery, The Open University
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C O U R S E L E C T U R E Naming Moons Notes taken on January 23, 2017 by Edward Tanguay |
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the right to name moons and features on their surfaces belongs to a body known as the International Astronomical Union (IAU)
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founded in 1919
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if you find a new moon, you suggest a name to the IAU but they don't have to accept it
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today, when a moon is discovered
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it is given a provisional name, e.g. S/2005 P1
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S = Satellite
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2005 = year of discovery
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P = primary body, in this case, Pluto
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1 = first moon of Pluto discovered that year
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later when the discovery has been confirmed, the IAU gives it an official, permanent name
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in this case, S/2005 P1 became Hydra
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named after the snake-headed monster killed by Hercules
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but why Hydra
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when a new moon is discovered, it is given a name that fits in with the theme for names that have already been chosen for moons of that planet
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moons of Pluto are named after figures with a connection to Hades
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Galileo started this tradition
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when he discovered the first four moons of Jupiter, there were no rules about naming moons
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he used Roman numerals, so we had Jupiter I, Jupiter II, etc.
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Simon Marius, a rival of Galileo
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proposed a mythological theme
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since the planet was named after the Roman god Jupiter, or Zeus, why not name the moons after the lovers of Zeus
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discovered in 1610
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Io
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mortal lover of Zeus
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ancestor of Hercules
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Hera turned her into a cow
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Europa
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mother of King Minos of Crete
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abducted by Zeus in the form of a white bull
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mentioned in Iliad
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Ganymede
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homeland was Troy
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son of Tros
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abducted by Zeus in the form of an eagle
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Homer describes him as the most beautiful of mortals
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Callisto
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daughter of Lycaon, king of Arcadia
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took a vow to remain a virgin
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to have sex with her, Zeus disguised himself as Artemis (Diana) herself, in order to lure her into his embrace
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Callisto was discovered pregnant and was then turned into a bear
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gave birth to a son called Arcas
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Zeus placed them both in the sky as the constellations Ursa Major, called Arktos [αρκτος], the "Bear" and Ursa Minor.
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16 newer moons are named after other relations with Zeus, e.g.
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1892 Amalthea
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the most-frequently mentioned foster-mother of Zeus
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located in Crete
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1904 Himalia
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a nymph of the eastern end of the island of Rhodes, Zeus was enamoured with her and she produced three sons with him
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1905 Elara
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Zeus fell in love with Elara and hid her from his wife Hera's jealousy by placing her deep beneath the Earth. This was where she gave birth to Tityos, a giant who is sometimes said to be the son of Gaia, the Earth goddess, for this reason. It is further added that Elara died in labour because of the enormous size of her baby
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1974 Leda
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admired by Zeus, who seduced her in the guise of a swan
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moons of Saturn
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five largest moons were discovered by Christian Huegens (1629-1695)
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and Giovanni Domenico Cassini (1625-1712)
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Huegens followed Galileo's conventions and gave the moons numbers rather than names
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when Sir William Hershel (1738-1822) discovered two other moons of Saturn
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also declined to name them
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his son, Sir John Hershel, settled the matter
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since Saturn was the Greek equivalent of Cronos, the leader of the Titans, Sir John named the largest moon Titan
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the other moons were named after other Titans
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Iapetus
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son of Uranus and Gaia
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father of Atlas, Prometheus, Epimetheus and Menoetius.
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Tethys
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daughter of Uranus and Gaia
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wife of her brother the Titan-god Oceanus
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Dione
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daughter of Okeanos and Tethys, hence an Oceanid, a water-nymph. She is otherwise called a daughter of Gaia
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Rhea
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daughter of the earth goddess Gaia and the sky god Uranus, and sister and wife to Cronus
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the two innermost moons were named after the Titan's half brothers, two giants
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Mimas
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Mimas was one of the Giants, the offspring of Gaia, born from the blood of the castrated Uranus
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Enceladus
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one of the Giants, the offspring of Gaia (Earth), and Uranus (Sky). Enceladus was the traditional opponent of Athena during the Gigantomachy, the war between the Giants and the gods, and was said to be buried under Mount Etna in Sicily
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the pace of discovers meant that astronomers were running out of Greek and Roman names
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so gods from other cultures are used
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Norse
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Fenrir
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named after monstrous Norse wolf Fenrisulfr
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Gallic
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Inuit
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Sir John Hershel
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also discovered moons of Uranus, the planet discovered by his father
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Uranus is the god of the air
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took his inspiration from English literature
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Oberon (1787)
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Oberon, the king of the fairies in Shakespeare's A Midsummer Night's Dream.
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Titania (1787)
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Titania, the queen of the fairies in Shakespeare's A Midsummer Night's Dream
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Ariel
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named after the leading sylph in The Rape of the Lock
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also the name of the spirit who serves Prospero in Shakespeare's The Tempest
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Umbriel
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Umbriel is the "dusky melancholy sprite" in Alexander Pope's The Rape of the Lock, and the name suggests the Latin umbra, meaning shadow
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as more moons were discovered, they were named after characters in Shakespeare's plays
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Ophelia
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moon of Uranus
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named after the daughter of Polonius in Hamlet
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Cordelia
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King Lear
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Desdemona
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Othello
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Margaret
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Much Ado About Nothing
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Neptune's first moon
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discovered by William Lassell (1799-1880) but he had nothing to do with naming it
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naming duties fell to the French astronomer Camille Flammarion
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carried on with the mythical theme
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Neptune's moon was named Triton, the Greek sea god Triton [Τρίτων], the son of Poseidon (Neptune)
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second moon
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Nereid
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named after the Nereids, sea-nymphs of Greek mythology and attendants of the god Poseidon
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later moons were also named after water spirits
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Larissa
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a nymph from Thessaly
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Proteus
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an early sea-god or god of rivers and oceanic bodies of water, one of several deities whom Homer calls the "Old Man of the Sea"
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Galatea [Γαλάτεια]
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"she who is milk-white"
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the statue carved of ivory by Pygmalion of Cyprus, which then came to life
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Mars
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1887 tiny moons
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Phobos ("fear")
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Deimos ("terror")
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Phobos (panic/fear) and Deimos (terror/dread) accompanied their father Ares, god of war, into battle
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dwarf planets
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Pluto, the god of the underworld
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moons are related to Hades
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Charon [KAIR-on]
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the boatman who ferried the dead across the river Styx
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Kerberos
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the many-headed dog
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Hydra
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the snake-headed monster