Slide1 : Have you ever wanted to know who named the planets and why?
Who decides what to name all the objects in the sky?
Slide2 : The International Astronomical Union (IAU) has been in charge of naming solar system objects since 1919
They have internationally accepted rules for naming planets, satellites, asteroids, and other objects
The discoverer of an object does have the privilege of suggesting a name to the IAU
Slide3 : Before the 1900’s the only objects that were named were the planets and the asteroids
The planets were named after Roman and Greek mythological characters
They were named according to their movements and appearance, and these names became standard over the millennia Early Greek model of the solar system
Slide4 : Since there are no more undiscovered planets, the IAU focuses now on naming moons, asteroids, comets, and minor planets
Contrary to some reports, it is not possible to buy a name of a minor object—to name one yourself you need to go out and discover one!
Slide5 : It is impossible to say who first named our home planet Earth
Earth is Old English and German in origin
It is related to the Old Saxon “ertha”, the Dutch “aerde”, and the German “erda”
It seems likely that ancient people used Earth to mean “land” and it became natural to use it for the whole planet
Slide6 : The name for the Moon, Earth’s satellite, is of Anglo-Saxon derivation and refers to a natural satellite of a planet (it is capitalized when it refers to our satellite)
It is sometimes called Luna (Latin), or Selene (Greek), but its official name is Moon
Slide7 : It is appropriate that the planet Mercury was named after the fleet-footed Roman god because it appears to move so swiftly, racing around the Sun in only 88 days
Venus, the planet that appears the brightest and most beautiful, was named after the Roman goddess of beauty and love Composite image of Mercury
by Mariner 10 Hubble Telescope
image of Venus
Slide8 : The planet Mars was named after the Roman god of war (Greek: Ares) because of its red, bloodlike color
Mars’ satellite Phobos was named for one of the horses that drew Mars’ chariot
Its other satellite Deimos was named for one of Mars’ companions Mars’ moons, Phobos & Deimos, as seen against
the planet’s glare in a composite image taken
by Johannes Schedler in 2004
Slide9 : Jupiter, the largest and most massive of the planets, was named after the most important Roman god (Greek: Zeus)
Jupiter’s satellites were named after mythological characters who have some relationship with the god (wives, lovers, daughters, etc)
Jupiter and four of its moons:
Io, Europa, Ganymede, and Callisto
(composite image)
Slide10 : The planet Saturn was named after the Roman god of farming (Greek: Cronos) who was also the father of Jupiter (Zeus)
Some of Saturn’s satellites were named for the Titans who were brothers and sisters of Saturn
The newest satellites were named for Gallic (ancient France), Norse, and Inuit (Eskimo) giants Saturn and some of its moons
(diagram from NASA)
Slide11 : The planet Uranus, discovered in 1781, was named for the Greek god of the sky
Uranus’ satellites were named for characters in the works of William Shakespeare and Alexander Pope Composite image taken by Voyager 2 in 1986
of Uranus (blue) and five of its moons: Umbriel,
Oberon, Titania, Miranda, and Ariel
(clockwise from top left)
Slide12 : The planet Neptune, discovered in 1846, was named for the Roman god of the sea because of its blue color
Neptune’s satellites were named after mythological characters that have some relationship with Neptune (goddesses, lovers, daughters, sea nymphs, etc) Neptune and one of its moons Triton (left)
taken by Hubble Telescope in 2001
Slide13 : Pluto, because of it’s small size and distance from the Sun, was named after the Roman god of the underworld (Greek: Hades), who was able to render himself invisible
Pluto’s satellite, Charon, was the mythological boatman who ferried souls across the river Styx to Pluto for judgment
In 2005 two more moons were discovered, Nix (named for the Greek goddess of dark and light) and Hydra (named for the monster that guards the waters of Pluto’s underworld) Pluto and its three moons taken by
Hubble Telescope
Slide14 : Asteroids were first named after mythological figures but as these names started to run out, others were used (famous people, literary characters, discoverers and their wives, and even television characters
Asteroid names are preceded by the number of the order of discovery (e.g. 1 Ceres, 433 Eros, 243 Ida, 951 Gaspra, 253 Mathilde)
Slide15 : Comets are named after their discoverer(s) and they are also given a designation relating to the year of discovery
For example the comet Hyakutake is officially classified as C/1996 B2: C means long-period comet (P means short- period and D means defunct), 1996 is the year of discovery, B indicates it was discovered in the second half of January, and 2 means it was the second comet discovered in that year Comet Hyakutake taken in Arizona
by Rick Scott & Joe Orman
Slide16 : Some names of famous comets: Halley’s Comet
P/1682 Q1
Short-period comet (P)
Discovered early Sept. (Q)
by Edmund Halley, 1st
comet discovered in 1682 Comet Hale-Bopp
C/1995 O1
Long-period comet (C)
Discovered early Aug. (O)
by Alan Hale & Thomas
Bopp, 1st comet discovered
in 1995 Comet Shoemaker-Levy 9
D/1993 F2
Defunct comet (D) (slammed into
Jupiter) Discovered late March (F)
by Carolyn & Eugene Shoemaker
and David Levy, 2nd comet
discovered in 1993
Slide17 : Provisional naming of dwarf planets and minor planets also follows a specific formula: the year, a letter to show the half-month (I & Z not used), and another letter to show the order in the half month (A is 1st, F is 6th, etc) that it was discovered
The final, official name is assigned when its orbit is determined
When Pluto was reclassified in August 2006 as a dwarf planet, it’s official name became 134340 Pluto Artist’s image of Pluto, Charon, and
the distant Sun
Slide18 : Eris (the largest dwarf planet, formerly nicknamed Xena) was provisionally known as 2003-UB313: discovered in 2003, in late Oct. (U), the 7827th object discovered during that time (B->2+313x25=7827)
It’s final name, assigned only after its orbit was determined, is 136199 Eris (the 136,999th object discovered)
It is named after the Greek goddess of strife and discord Artists concept of Eris and its moon
Dysnomia looking back towards
a distant Sun
Slide19 : Some names of other Minor Planets: 90377 Sedna
Named for the Inuit goddess that lives below the frigid Arctic Ocean
Artist’s image of Sedna
looking back toward the Sun 50000 Quaoar
Named after the creation god of Native American Tongva tribe Artist’s image of Quaoar
courtesy of NASA Artist’s image of
Varuna 20000 Varuna
Named after the Hindu
god of the ocean
Slide20 : Historically stars were named by ancient cultures with names that had special meaning for them
As telescopes began detecting fainter stars various catalogs began documenting them
A star’s official name contains the star’s coordinates for a particular epic (1950 or 2000) which accounts for the Earth’s precession and the motion of the star itself Hubble image of the star Sirius who’s
modern catalog name would be:
Sirius=HIC 32349=CCDM J06451-1643
Slide21 : Like stars, most galaxies do not have proper names but simply have a catalog number
The New General Catalog (NGC) is one of the largest catalog of deep sky objects
Another popular list astronomers use is the Messier Catalog (M) Andromeda Galaxy (M31) Eskimo Galaxy (NGC2392)