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Contest win will help Pluto moons' discoverer make his case for Vulcan

An image from the Hubble Space Telescope shows Pluto and its largest moon, Charon, surrounded by four smaller moons. P4 and P5 will be getting new names. One of them might be called Vulcan.M. Showalter / NASA / ESA

The organizer of a contest to name Pluto's two tiniest moons can't guarantee that either one of them will be called "Vulcan" — but now that the name nominated by the original captain on the "Star Trek" TV show has won first place in the voting, planetary scientist Mark Showalter promises to argue the best case he can.

"My starting position is that we should work with the names that received the most votes," Showalter told NBC News on Friday.

The "Pluto Rocks" voting concluded at noon ET Monday, and is being followed by a 1:30 p.m. Google+ Hangout sponsored by the SETI Institute, the place where Showalter works. Vulcan came out on top with 174,062 of the 450,324 votes cast. But don't expect Showalter to declare immediately that Vulcan is the choice for one of Pluto's moons.

"There will not be an announcement on Monday," he said.

For one thing, it's not totally up to Showalter to make the nomination. He's just one of the leading scientists on the discovery teams for P4 and P5, the two moons that were found in 2011 and 2012. All the members from each of the teams will have to agree on the names to be submitted to the International Astronomical Union for approval. Even then, the IAU could voice concerns about the names they submit, leading to alternate suggestions. Showalter said he's actually seen that happen in the case of the Uranian moon that ended up being called Cupid.

Kirk ... takes ... command

Vulcan wasn't on Showalter's initial list of prospects, but he added it to the ballot at the urging of William Shatner, the actor who played Captain James T. Kirk on the original "Star Trek" series in the late 1960s. Shatner favored the name because it was the fictional home planet of Kirk's pointy-eared science officer, Mr. Spock. "Let's hope the IAU thinks Vulcan is a good name," Shatner wrote in a tweet to his 1.35 million Twitter followers.

Showalter said Shatner's endorsement definitely skewed the results. "Early on, it's pretty clear there were some Trek fans who seem to have resorted to augmented voting technologies," Showalter said. But he's convinced that the groundswell of support for Vulcan is genuine, and he said he's "come up with a pretty good case" for using the name.

"I want people to feel that their vote counted," Showalter said.

The IAU's guidelines for Pluto's moons stipulate that they should be named after Greek or Roman gods who have some connection to the mythological underworld. Those guidelines worked for Pluto's three other moons, Charon (ferryman of the dead), Nix (goddess of darkness) and Hydra (a many-headed monster).

Vulcan has a family relationship to the underworld, in that he was Pluto's nephew. And in his capacity as the god of fire, Vulcan tended to hang out in the depths beneath Mount Etna and other volcanoes, rather than on the heights of Mount Olympus. That may not be Hell, exactly, but it's certainly the underworld.

Showalter admitted that it might be tricky to have the god of fire associated with one of the coldest places in the solar system. "It may well be there's a consensus that it's a great name, but not a great name for a moon of Pluto," he said. Also, the name Vulcan has been associated with a hypothetical planet that was thought to circle the sun within Mercury's orbit. The 19th-century French astronomer who discovered Neptune, Urbain Jean Joseph Le Verrier, spent fruitless years looking for it. Pluto's moon is in an entirely different place, but Showalter sees that as a potential plus.

"Maybe we'd be doing Le Verrier a favor by saying that when he was looking for the ninth planet inside Mercury's orbit, he was looking in the wrong direction," Showalter joked.

Some have said the name Vulcan should be reserved for a planet beyond our own solar system. In response, Showalter points out that there's no IAU procedure for giving names to extrasolar planets (beyond generic designations such as Kepler-37b or Gliese 163c). That situation may change if planet-naming ventures such as Uwingu take hold. But in the meantime, Showalter feels that Vulcan should at least be given a fair shot at solar system fame.

Another moon to name

So it's a sure thing that Showalter will try making the case for Vulcan. But what about the other Plutonian moon?

Cerberus held onto the No. 2 spot in the voting, with 99,432 votes, and so Showalter will argue the case for Cerberus as well. That name fits perfectly with the mythological underworld theme, because Cerberus was the three-headed hound that guarded the gates of the underworld.

One drawback is that there's already an asteroid named Cerberus, and the IAU doesn't want newly named celestial bodies to be confused with previously named objects. Showalter said there are at least two ways around that issue: One is to argue that the asteroid and the moon wouldn't be confused. The precedent for this is Io, a mythological name that refers to a Jovian moon as well as an asteroid. Another way out is to change the spelling slightly — say, to the Greek name Kerberos. One precedent for this is the Plutonian moon Nix, which uses an alternate spelling to avoid confusion with the asteroid Nyx. (By the way, there's already an asteroid named Vulcano, but that name is considered different enough from Vulcan,)

Opening the moon-naming process up to a vote has been a lot of work, even if it's a non-binding vote, and Showalter said he doubts that he'll do it again. But he's gratified by the response: The contest attracted hundreds of thousands of votes from scores of countries around the world, generated more than 30,000 write-in suggestions for names, and gave Pluto fans and "Star Trek" fans lots to think about.

What would Spock think about all this? Leonard Nimoy, the actor who played the alien on the original "Star Trek" show, said via Twitter that "'Vulcan' is the logical choice." I can imagine Spock saying that, but I can also imagine him uttering just one word. ...

More about Pluto and its moons:

This report was originally published Friday and was updated with the results of the "Pluto Rocks" contest on Monday.

Alan Boyle is's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.