How do we name our Solar System?

We all remember learning the mnemonic device in elementary school: My Very Excellent Mother Just Served Us Noodles (or whatever variation you prefer). Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, the eight planets of our solar system. But what do these names actually mean? How do planets and moons and other stuff in our solar system even get their names? And what about the various mountains and crevices on the actual planets, do those features get names?

Of course, all languages have their own names for the planets and their moons, but when discussing the official scientific names we must turn to the IAU. The job of the International Astronomical Union is ” to promote and safeguard the science of astronomy in all its aspects,” including the official names of all things in space. In their terms, “unambiguous astronomical nomenclature.”

There are a few steps on deciding on these official names, and it all starts with the discovery of the moon or feature. Once the thing-to-be-named is properly confirmed to exist, several names are considered by a Task Group. Names successfully reviewed by the Task Group move onto the Working Group for Planetary System Nomenclature (WGPSN). If the WGPSN gives the final approval for the name, it is immediately entered in the Gazetteer of Planetary Nomenclature, the official reference for all solar system names.

Let’s take a short flip through of the Gazetteer and dive into some planetary naming.

Mercury – named after the Roman god of commerce, travel, and thieves because it moves so fast across the sky. Mercury has no moons. Themes for naming planetary features include abandoned cities, words for “snake” and “hot” in different languages, and significant works of architecture.

Venus – named after the Roman goddess of love and beauty, because it is the brightest and most beautiful planet. Venus also has no moons. Themes for naming planetary features include different types of goddesses, mythological heroines, and women who have made outstanding contributions to their field.

The Moon – in other languages it is known as Luna, Lune, Mond, and Selene. The Moon is Earth’s satellite. Themes for naming features on the Moon include significant cosmonauts, astronomers, and scientists, as well Latin terms for weather and other abstract concepts. Although the Moon has the most well-developed nomenclature since it is the easiest to study, only twenty eight craters on the Moon are named for women out of the 1586 craters. For more information on this disparity and these remarkable women, I would recommend reading The Women of the Moon by Daniel R. Altschuler and Fernando J. Ballesteros.

Mars – named for the Roman god of war, appropriate for the striking red planet. Mars has two moons, Phobos and Deimos (fear and panic respectively). These are the names of the mythological horses which pulled Mars’ chariot. Themes for naming planetary features include names from classical mythology, names of rivers, and small towns and villages of the world. Features on Phobos are named after scientists who studied these two moons and people/places from Gulliver’s Travels by Jonathan Swift. Features on Deimos are named after authors who wrote about the Martian satellites.

Jupiter – named after the Roman King of the gods, the god of sky and thunder, which is an appropriate name for the largest planet in our solar system. Jupiter has 79 moons, which are all named after the mythological children of Jupiter. Themes of the features on the satellites include:

• Io – heroes and gods related to fire, sun, and volcanoes, mythical blacksmiths, and people/places from Dante’s Inferno
• Europa – gods, heroes, and places from Celtic myths, as well as Celtic stone rows
• Ganymede – gods and heroes of the ancient Fertile Crescent civilization, places from Egyptian myths, and astronomers who discovered Jovian moons
• Callisto – all names are drawn from myths and stories of cultures of the Far North, such as Norse, Inuit, Sami, etc.

Saturn – named for the Roman god of wealth and agriculture. In Greek mythology, Saturn’s equivalent is the father of Jupiter’s Greek equivalent. Saturn has 82 moons, which are named after Greek giants, titans, and titan descendants. Themes of the features on some of the satellites include:

• Mimas – people/places from Le Morte d’Arthur legends
• Enceladus – people/places from Burton’s Arabian Nights
• Tethys – people/places from Homer’s Odyssey
• Dione – people/places from Virgil’s Aeneid
• Titan – islands on Earth that are not politically independent, people/places from Middle-earth (from the novels of J.R.R. Tolkein), characters from the Foundation series by Isaac Asimov, and names of planets from the Dune series by Frank Herbert

Uranus – named after the Greek deity of the heavens, who is the father of the Greek equivalent of Saturn. Sir William Herschel, who first discovered Uranus, originally wanted to name it “Georgium Sidus” or the Georgian planet in honor of King George the III. Uranus has 27 moons, which are named for magical spirits from Shakespeare or Alexander Pope. The reasoning could be that Uranus, as the god of the air, would be attended by spirits of that realm such as fairies and sylphs. Themes of the features on some of the satellites include:

• Puck – mischievous spirits
• Ariel – light spirits
• Umbriel – dark spirits
• Oberon – Shakespearean tragic heroes and places

Neptune – named after the Roman god of the seas, a perfect match for Neptune’s bright blue color. Neptune has 14 moons, named after minor water gods in Greek mythology. Themes of the features on these satellites follow the same trend.

Dwarf Planets

Pluto – named after the Roman god of the underworld. Pluto has 5 moons, which are also named in relation to the underworld. Features on Pluto also follow this naming theme. Themes of the features on some of the satellites include:

• Charon – destinations of mythical space and fictional vessels/voyagers of space and other exploration
• Kerberos – dogs from literature, history, and mythology
• Hydra – legendary serpents and dragons

Ceres – named after the Roman goddess of corn and agriculture. Ceres has no moons, and its features are named after gods and goddesses of agriculture and agricultural festivals.

Sources: Gazetteer of Planetary Nomenclature, Uranus Facts, NASA’s StarChild Questions, The 219 Moons of the Planets