The Charon name thing is starting to get to me. Every meeting, press brief, interview I hear the name of Pluto's largest moon pronounced differently. I swear to Hades, sometimes I hear the same person pronounce it two ways. Granted, I'm jet lagged, sleep deprived, and the coffee in the press room is lukewarm and from Dunkin' Donuts (what gives, NASA?), but I'm starting to feel like someone is messing with me.

So I started asking people—mostly people wearing black polos emblazoned with the nine-sided New Horizons logo: "How do you pronounce the name of Pluto's largest moon?" I didn't get far enough to get meaningful survey results, but I did find out why the results would always be mixed.

That's because I ran into Will Grundy, one of New Horizons' co-investigators and an astronomer at Lowell Observatory. "Well, the original Greek way to pronounce it would be Gheghron," he says, shoving the word out of the back of his throat like it's a big, fat Klingon loogie. Gross, but makes sense. After all, Charon was the ferryman who brought damned souls across the river Styx into Pluto's realm. But the astronomer who gave the moon its name didn't even know about the Greek myth when he picked the name1.

Jim Christy, who discovered the moon in 1978, had promised his wife Charlene he would name the object after her. See, his wife's name is Charlene, so he took her nickname—Char—and threw an -on in on the end to science things up.

Some of his colleagues had been lobbying to name the moon Persephone (Pluto the god's abducted queen), so he started doing some research. That's when he stumbled across the Greek myth, and with that argument in hand the astronomical community informally adopted Charon later that year, and then formally in 1985.

So what's that got to do with the pronunciation? Most astronomers, says Grundy, pronounce it "Share-on, as a tip of the hat to Jim and his wife." But then he shrugs and says everybody flops back and forth all the time. "We all say it both ways in a single sentence."

Really? Guys, that is a hell of a way to come up with nomenclature. Lunacy, even.

1 Update 14:26 ET July 20 2015. This Sky & Telescope article from 2008 has the entire naming episode in full detail.