SCIENCE
How did NASA set its horizons on our favorite dwarf planet?
Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.

Photograph by NASA/JHUAPL/SwRI
Discussion Ideas
Note to teachers: You’ll definitely want your science fiction fans to be a part of this discussion!
- Take a look at the guidelines for naming geographic features of Pluto and its moons. They seem preoccupied with the underworld—Hell, the Elysian Fields, etc. Why?
- Pluto itself, whose name was suggested by an 11-year-old-girl, is named after the Roman god of the underworld. Keeping names associated with cultural references to the underworld is nicely thematic.
- Another example of a theme in planetary nomenclature is the moons of Uranus, named after characters in the works of William Shakespeare (Miranda, Portia, Puck) and Alexander Pope (Umbriel, Belinda).
- Pluto itself, whose name was suggested by an 11-year-old-girl, is named after the Roman god of the underworld. Keeping names associated with cultural references to the underworld is nicely thematic.
- Are there any geographic features that have already been informally named?
- Yes, and they are awesome. (Zoom in below.) An informal naming campaign was held last year. Pop culture quiz: How many references do you recognize?

Map by NASA, SETI Institute
- What are some examples of names appropriate for the geographic naming guidelines for Pluto? Take a look at this spreadsheet of the informal naming criteria for some help. (And get some reading ideas!)
- Gods, goddesses, and other beings associated with the Underworld from mythology, folklore, and literature.
- An informal name that meets these criteria is the Cthulhu Regio, named after Cthulhu, the horror deity in the works of H.P. Lovecraft.
- A regio is simply a large, distinguishable geographic region.
- Other examples might include Mictlantecuhtli, an Aztec deity, or Yama, a Hindu lord of death.
- Names for the Underworld and for Underworld locales from mythology, folklore, and literature.
- An informal name that meets these criteria is the Pandemonium Dorsa, named after the capital of Hell in John Milton’s Paradise Lost.
- Dorsa are geologic ridges.
- Other examples might include Annwn, from Welsh mythology, or Yomi, from Japanese (Shinto) mythology.
- Heroes and other explorers of the Underworld.
- An informal name that meets these criteria is the Beatrice Fossa, named after Dante’s deceased girlfriend and tour guide in The Divine Comedy.
- Fossae are a long, shallow depressions.
- Another example might be Tiresias, a guiding figure in the Underworld of Homer’s Odyssey.
- Scientists and engineers associated with Pluto and the Kuiper Belt.
- An informal name that meets these criteria currently takes up the biggest space on the planet: the Tombaugh Regio. Clyde Tombaugh is the astronomer who discovered “Planet X”—Pluto—in 1930.
- Our guess is that Tombaugh’s name will ultimately be attached to something on the dwarf planet he discovered when the formal names are revealed.
- An informal name that meets these criteria currently takes up the biggest space on the planet: the Tombaugh Regio. Clyde Tombaugh is the astronomer who discovered “Planet X”—Pluto—in 1930.
- Pioneering space missions and spacecraft.
- An informal name that meets these criteria is the Astrid Colles, named after Sweden’s micro-satellites, which studied Earth’s aurorae.
- Colles are small hills.
- Another example might be New Horizons itself!
- Historic pioneers who crossed new horizons in the exploration of the Earth, sea and sky.
- An informal name that meets these criteria is the Cousteau Rupes, named after Jacques-Yves Cousteau, a legendary oceanographer and explorer.
- Rupes are steep cliffs.
- Another example might be Zheng He, a Chinese merchant explorer who led 15th-century expeditions throughout the Indian Ocean.
- Gods, goddesses, and other beings associated with the Underworld from mythology, folklore, and literature.
- What are some examples of names appropriate for the geographic naming guidelines for Charon?
- Destinations and milestones of fictional space and other exploration.
- An informal name that meets these criteria is the Vulcan Planum, named after the home planet of Spock, from the TV series Star Trek.
- Plana are plateaus or high ridges.
- Another example might be Pandora, the planet explored in the movie Avatar.
- Fictional and mythological vessels of space and other exploration.
- An informal name that meets these criteria is the Tardis Chasma, named after the police-box time machine in the TV series Doctor Who.
- A chasma is simply a chasm, or deep and long depression.
- Another example might be Nostromo, the spaceship from the film Alien.
- Fictional and mythological voyagers, travellers and explorers.
- An informal name that meets these criteria is the Leia Organa Crater, named after a heroine of the Star Wars trilogy.
- Craters are bowl-shaped depressions created by the impact of a meteorite, volcanic activity, or an explosion.
- Another example might be Dave Lister, a hero of the TV sci-fi comedy Red Dwarf.
- Authors and artists associated with space exploration, especially Pluto and the Kuiper Belt.
- An informal name that meets these criteria is Butler Mons, named after the brilliant sci-fi author Octavia Butler.
- A mons is a singular mountain.
- Another example might be Osamu Tezuka, the “godfather of manga” who was a tremendous influence on Japanese science fiction.
- Destinations and milestones of fictional space and other exploration.
- What are some examples of river gods, the guidelines for the Plutonian moon Styx?
- Styx itself is named after a river of the Underworld in Greek mythology.
- Some examples might include He-Bo, god of the Yellow River (China) or Khnum, a god of the Nile River (Egypt).
- Features these names could identify might be a macula (dark spot) or vallis (valley).
- What are some examples of night-time gods, the guidelines for the Plutonian moon Nix?
- Nix itself is named after the Greek goddess of the night.
- Another example might be Hine-nui-te-pō, the (female) ruler of the Maori underworld.
- Features these names could identify might be linea (elongated markings) or a cavus (deep-sided depression).
- What are some examples of dogs from literature, mythology, and history, the guidelines for the Plutonian moon Kerberos?
- Kerberos itself is a variant spelling for Cerberus, the three-headed guard-dog of the Greek Underworld, Hades.
- Other examples might include Fenrir, the legendary wolf of Norse mythology, or Anubis, the jackal-headed god of Egyptian mythology.
- Features these names could identify might be montes (mountain ranges) or catenae (chain of craters).
- What are some examples of legendary serpents or dragons, the guidelines for the Plutonian moon Hydra?
- Hydra itself is named after a legendary water monster who tangled with Hercules in Roman mythology.
- Other examples might include the Rainbow Serpent of Aboriginal Australian mythology, or Fafnir, from Norse mythology.
- Features these names could identify might be a terra (large land mass) or a corona (oval feature).
TEACHERS TOOLKIT
NASA: New Horizons, IAU Set Pluto Naming Themes
Nat Geo: Pluto on the Horizon study guide
Jet Propulsion Laboratory: Informal Names for Features on Pluto or Our Pluto
International Astronomical Union: Descriptor Terms (Feature Types)
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