How the Newest Moons Get Their Names

A new, far-flung moon orbiting Neptune was discovered earlier in July, bringing that planet's cache of known moons up to 14. Now, what -- and how -- will scientists name it?

This computer-generated montage shows Neptune and Triton, Neptune's largest moon, from January 1990. Photo by SSPL/Getty Images.

A new, far-flung moon orbiting Neptune was discovered earlier this month and announced this week, bringing that planet's cache of known moons up to 14. Now scientists are faced with the daunting process of naming it.

They can't call it just anything. The criteria is pretty darn strict. According to Mark Showalter of Mountain View's SETI Institute, who spotted the thing against all odds -- it was hidden deep in Hubble Space Telescope data -- its name must derive from a Greek or Roman deity. And it must be associated with Neptune or Poseidon or the sea. Which, he said, covers a lot more territory than you'd think -- those Roman and Greek gods had a lot of kids.

He is leaning toward naming the moon after the Cyclops, Polyphemus, the gigantic one-eyed son of Poseidon and Thoosa, a sea nymph. Polyphemus is best known for his role in Homer's epic poem, the Odyssey. You may remember that after Odysseus and 12 of his crew landed on the island, Cyclopes, Polyphemus trapped them in a cave with a boulder, devoured two of the men for dinner, fell asleep and then ate two more for breakfast. The remaining men eventually escaped after plunging the creature in the eye and blinding him.

"I happen to like hideous monsters myself," Showalter told me. "That's just a personal bias."

The guidelines are laid out by the International Astronomical Union and can be found here.

But Showalter may take another route and crowdsource the moon, which is currently referred to as S/2004 N 1. That's what he did with the two newest Pluto moons, which he also discovered. He held an Internet contest for the names. The winners were Kerberos, named for the three-headed dog that guarded the entrance to Hades, the underworld in Greek mythology, and Styx, after the river that separated Earth and underworld.

Pluto's satellites and moons are named after mythological characters related to Hades and the classical Greek and Roman Underworld, according to the IAU. Moons orbiting Uranus are named for characters from Shakespeare's plays and from Pope's "Rape of the Lock." In the Saturnian system, they're named for 'Greco-Roman titans, descendants of the titans, the Roman god of the beginning, and giants from Greco-Roman and other mythologies." And in Jupiter, they're named after Zeus's lovers and descendants.

The newest moon is tiny (about 12 miles in diameter), located between fellow moons Larissa and Proteus, and it zips around Neptune every 23 hours.

And as to whether there are more, undiscovered moons around the planet?

"I would say [the likelihood is] very high," Showalter said. "It would be a foolish prediction to say, we've found the last one. At this point would have to be less than half as bright as M-14, or we would have seen it."


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