Origins of the names of the celestial bodies

The names of the planets are based on mythological characters. Below is an overview of the planets, their moons and satellites, and the origin of their names.

Mercury

The first planet from the sun and the eighth largest.
In Roman mythology Mercury was the god of trade and profit, merchants and travelers.

Venus

The second planet from the Sun and the sixth larges.
In Roman mythology Venus was the goddess of love and beauty.

Earth

The third planet from the Sun and the fifth largest.
It is the only planet whose name does not derive from Greek/Roman mythology.

Moons

  • The Moon is the only natural satellite of Earth.
    It was called Luna by the Romans, Mani by the Norse, and Selene by the Greeks.

Mars

Mars is the fourth planet from the Sun and the seventh largest.
In Roman mythology Mars was the god of war.

Moons

  • Phobos is the larger and innermost of Mars' two moons, but one of the smallest in the solar system.
    In Greek mythology Phobos was the personification of fear and terror.
  • Deimos is the smaller and outermost of Mars' two moons, and the smallest known moon in the solar system.
    In Greek mythology Deimos personified dread.

Jupiter

The fifth planet from the Sun and the largest.
Jupiter (Greek: Zeus) was the supreme god of the Roman pantheon; a god of light and sky, and protector of the state and its laws.

Satellites

  • Metis is the innermost of Jupiter's known satellites.
    In Greek mythology, Metis was the personification of wisdom; the first wife of Zeus.
  • Adrastea is the second of Jupiter's known satellites.
    In Greek mythology the goddess Adrastea punished human injustice.
  • Amalthea is the third of Jupiter's known satellites.
    In Greek mythology, Amaltheia was the divine goat (or nymph) who suckled the infant Zeus on Crete.
  • Thebe is the fourth of Jupiter's known satellites.
    In Greek mythology Thebe was a nymph, the daughter of the river god Asopus.
  • Io is the fifth of Jupiter's known satellites and the third largest; it is the innermost of the Galilean moons. Io is slightly larger than Earth's Moon.
    In Greek mythology, Io was a princess whom Zeus transformed into a white heifer to hide her from his ever jealous wife Hera.
  • Europa is the sixth of Jupiter's known satellites and the fourth largest; it is the second of the Galilean moons. Europa is slightly smaller than the Earth's Moon.
    In Greek mythology Europa was a Phoenician princess who was abducted to Crete by Zeus.
  • Ganymede is the seventh and largest of Jupiter's known satellites. Ganymede is the third of the Galilean moons.
    In Greek mythology Ganymede was a Trojan prince of great beauty whom Zeus made cup bearer to the gods.
  • Callisto is the eighth of Jupiter's known satellites and the second largest. It is the outermost of the Galilean moons.
    In Greek mythology Callisto was a nymph, beloved of Zeus. Hera changed the woman into a bear and Zeus then placed her in the sky as the constellation Ursa Major.
  • Leda is the ninth of Jupiter's known satellites and the smallest.
    In Greek mythology Leda was queen of Sparta. Visited by Zeus in the form of a swan, she became the mother of Helen and Polydeuces (Pollux).
  • Himalia is the tenth of Jupiter's known satellites.
    In Greek mythology Himalia was a nymph who bore three sons of Zeus.
  • Lysithea is the eleventh of Jupiter's known satellites.
    In Greek mythology Lysithea was a daughter of Oceanus and one of Zeus' many lovers.
  • Elara is the twelfth of Jupiter's known satellites.
    In Greek mythology Elara was the mother by Zeus of the giant Tityus.
  • Ananke is the thirteenth of Jupiter's known satellites.
    In Greek mythology Ananke was the personification of unalterable necessity, or fate.
  • Carme is the fourteenth of Jupiter's known satellites.
    In Greek mythology, Carme is the mother of Britomartis, a Cretan goddess.
  • Pasiphae is the fifteenth of Jupiter's known satellites.
    In Greek mythology Pasiphae was the wife of Minos and mother, by a white bull, of the Minotaur.
  • Sinope is the outermost of Jupiter's known satellites.
    In Greek mythology Sinope was a daughter of Asopus, and mother of Syrus.

Saturn

Saturn is the sixth planet from the Sun and the second largest.
In Roman mythology, Saturn is the god of agriculture.

Satellites

  • Pan is the innermost of Saturn's known satellites.
    In Greek mythology Pan the god of shepherds and flocks.
  • Atlas is the second of Saturn's known satellites.
    In Greek mythology Atlas is a Titan condemned to bear the world upon his shoulders as punishment for attempting to storm the heavens.
  • Prometheus is the third of Saturn's known satellites.
    In Greek mythology Prometheus was a Titan who stole fire from the gods and gave it to humankind.
  • Pandora is the fourth of Saturn's known satellites.
    In Greek mythology Pandora was the first woman on earth. She was given to Prometheus, bearing a jar which she was not to open. When she did, all evil contained escaped, except for one thing: Hope.
  • Epimetheus is the fifth of Saturn's known satellites.
    In Greek mythology Epimetheus was the brother of Prometheus and husband of Pandora.
  • Janus is the sixth of Saturn's known satellites.
    In Roman mythology Janus was the god of gates and doorways, beginnings and endings.
  • Mimas is the seventh of Saturn's known satellites.
    In Greek mythology Mimas was a giant, slain by Heracles.
  • Enceladus is the eighth of Saturn's known satellites.
    In Greek mythology Enceladus was a giant who was killed by a lightning bolt sent by Zeus and buried beneath Mount Etna by Athena.
  • Tethys is the ninth of Saturn's known satellites.
    In Greek mythology Tethys was the personification of the fertile ocean; wife of Oceanus.
  • Telesto is the tenth of Saturn's known satellites.
    In Greek mythology Telesto was a sea nymph, a daughter of Oceanus and Tethys.
  • Calypso is the eleventh of Saturn's known satellites.
    In Greek mythology Calypso was a nymph who held Odysseus prisoner on her island Ogygia for seven years.
  • Dione is the twelfth of Saturn's known satellites.
    In Greek mythology Dione was the mother of Aphrodite by Zeus, according to some traditions.
  • Helene is the thirteenth of Saturn's known satellites.
    In Greek mythology Helene was an Amazon who battled with Achilles.
  • Rhea is the fourteenth of Saturn's known satellites and the second largest.
    In Greek mythology Rhea was the mother of the gods, sister and wife of Cronus.
  • Titan is the fifteenth of Saturn's known satellites and the largest.
    In Greek mythology the Titans were a race of god-like giants, the personifications of the forces of nature.
  • Hyperion is the sixteenth of Saturn's known satellites.
    In Greek mythology Hyperion was a Titan, father of the sun-god Helios.
  • Iapetus is the seventeenth of Saturn's known satellites and the third largest.
    In Greek mythology Iapetus, a Titan and father of Atlas, Prometheus, and Epimetheus.
  • Phoebe is the outermost of Saturn's known satellites. Phoebe is almost 4 times more distant from Saturn than its nearest neighbor (Iapetus).
    In Greek mythology Phoebe is a Titaness, wife of Coeus and mother of Leto and Asteria.

Uranus

The seventh planet from the Sun and the third largest (by diameter).
Uranus is the ancient Greek god of the Heavens, but was dethroned by his son Cronus.

The innermost ten moons
Cordelia, Ophelia, Bianca, Cressida, Desdemona, Juliet, Portia, Rosalind, Belinda, and Puck.

Satellites
Miranda, Ariel, Umbriel, Titania, and Oberon.

Note: The names of the moons and satellites of Uranus are an exception. While all the other moons and satellites are named after characters from Greek and Roman mythology, those of Uranus have literary names (from Shakespeare and Pope). Uranus is also the only planet that is named after a Greek deity.

Neptune

The eighth from the Sun and the fourth largest (by diameter).
In Roman mythology Neptune was the god of the sea.

Satellites

  • Naiad is the innermost of Neptune's known satellites.
    In Greek mythology the naiades were the nymphs who lived in and presided over brooks, springs, and fountains.
  • Thalassa is the second of Neptune's known satellites.
    In Greek mythology, Thalassa is the Greek word for "sea."
  • Despina is the third of Neptune's known satellites.
    In Greek mythology Despina was a sea nymph, a daughter of Poseidon.
  • Galatea is the fourth of Neptune's known satellites.
    In Greek mythology Galatea was a Sicilian Nereid loved by the youth Acis.
  • Larissa is the fifth of Neptune's known satellites.
    In Greek mythology Larissa was, according to some sources, the mother of Pelasgus by Poseidon.
  • Proteus is the sixth of Neptune's known satellites and the second largest.
    In Greek mythology Proteus was a prophetic sea divinity who could change his shape at will.
  • Triton is the seventh and by far the largest of Neptune's satellites.
    In Greek mythology Triton was a sea divinity, half man and half fish.
  • Nereid is the outermost of Neptune's known satellites and the third largest.
    In Greek mythology the Nereides are the 50 daughters of Nereus and Doris.

Pluto

Pluto is the farthest "planet" from the Sun (usually) and the smallest.
[On August 24, 2006, Pluto was stripped of its planetary status and is now called a dwarf planet.]
In Roman mythology, Pluto (Greek: Hades) is the god of the underworld.

Satellites

  • Charon is Pluto's only (known) satellite.
    In Greek mythology Charon ferried the dead across the river Styx.

Eris

The "tenth planet," a large ice object formerly known as 2003 UB313, and slightly larger than Pluto. It is officially designated as 136199 Eris.
In Greek mythology, Eris is the goddess of discord who helped spark the Trojan War.

Moons

  • Dysnomia is Eris' only (known) moon and is about 8 times smaller. The official designation is (136199) Eris I Dysnomia.
    In Greek mythology Dysnomia is a daughter of Eris and a daemon of lawlessness.


For more on the planets, moons, and satellites in our solar system, try The Nine Planets by Bill Arnett. More information on the "official" astronomical names can be found here.