September 15, 2006

The latest astronomenclature: Eris and Dysnomia

Say good-bye to Xena. The large object discovered by Mike Brown in the Kuiper Belt out beyond Neptune has an official name, replacing the jocular moniker Brown and his team used in honor of the TV series Xena: Warrior Princess. It's now called Eris, according to a ruling by the executive committee of the International Astronomical Union. Eris is the Greek goddess of discord, so it's a fitting name for an object whose discovery led to chaos in the astronomical community, ultimately resulting in the sad demotion of Pluto to nothing more than a "dwarf planet." Pluto is supposed to be the "prototype" for the new category of dwarf planets, but it's actually smaller than Eris. Adding insult to injury, the dwarf planets will all have official names prefixed by unwieldy numbers (since they're now jockeying for position with an abundance of asteroids and other minor objects), so Eris is actually (136199) Eris, while Pluto is, ignominiously enough, (134340) Pluto.

The moon of Eris (formerly nicknamed Gabrielle, companion of Xena) is now called Dysnomia, after the goddess of lawlessness, a daughter of Eris. Fans of the Xena series will spot an inside joke there, since Xena was portrayed by Lucy Lawless. Brown has stated that this is no coincidence, but rather a covert tribute to the actress. And the name Dysnomia carries another hidden message. Pluto's moon was named Charon, which just so happens to share the first syllable [*] of Charlene, wife of Charon's discoverer Jim Christy. Similarly, Mike Brown's wife is named (surprise) Diane, and news reports say that Dysnomia will be "affectionately known by Brown's team as Di."

If the IAU wants to give discordant names to other dwarf planets discovered in the future, they'll have plenty to choose from. Hesiod's Theogony lists a number of other daughters of Eris, collectively known as the Kakodaimones (evil spirits plaguing humanity):

But abhorred Eris (Strife) bare painful Ponos (Toil), and Lethe (Forgetfulness), and Limos (Starvation), and the Algea (Pains), full of weeping, the Hysminai (Fightings) and the Makhai (Battles), the Phonoi (Murders) and the Androktasiai (Man-slaughters), the Neikea (Quarrels), the Pseudo-Logoi (Lies), the Amphilogiai (Disputes), and Dysnomia (Lawlessness) and Ate (Ruin), who share one another's natures, and Horkos (Oath) who does more damage than any other to earthly men, when anyone, of his knowledge, swears to a false oath.

Let's hope that our discordant astronomers are spared further ill effects of the Kakodaimones.

[* Steve of Languagehat points out that Charon is typically pronounced like Karen. So let's say Charon and Charlene share a graphemic opening, if not a phonemic one.]

Posted by Benjamin Zimmer at September 15, 2006 01:16 AM