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There has been a lot of debate recently about the demotion of Pluto as a planet. Pluto is a weird planet : it is the farthest one, has an eccentric orbit (where it becomes closer to the sun than Neptune at one point) and has a moon that is almost as large as itself. It's also discovered by Clyde Tombaugh, an American, a subtle and important fact, cause this whole discussion is mostly a political one.

The first proposition was to include Ceres (an asteroide between Mars and Jupiter) and Xena, recently discovered as the tenth planet, in the list as officially acknowledged planets. The problem with that resolution was that there are more objects in the solar system which would be classified as planets.

The second proposition was to remove Pluto as a planet, and call objects of its size as 'Plutons', or dwarf planets. However, the discussion is still open, and lots of scientist would like to see Pluto to reappear as planet.

Xena, the tenth planet, just got renamed as Eris, which is more according to the standard of giving planets the name of Roman and Greek gods. In Greek mythology, Eris is the goddess of warfare and strife. She stirs up jealousy and envy to cause fighting and anger among men. At the wedding of Peleus and Thetis, the parents of the Greek hero Achilles, all the gods with the exception of Eris were invited, and, enraged at her exclusion, she spitefully caused a quarrel among the goddesses that led to the Trojan war. In the astronomical world, Eris stirred up a great deal of trouble among the international astronomical community when the question of its proper designation led to a raucous meeting of the IAU in Prague. At the end of the conference, IAU members voted to demote Pluto and Eris to dwarf-planet status, leaving the solar system with only eight planets.

The satellite of Eris has received the offical name Dysnomia, who in Greek mythology is Eris' daughter and the demon spirit of lawlessness. As promised for the past year, the name Xena (and satellite Gabrielle) were simply placeholders while awaiting the IAU's decision on how an official name was to be proposed. As that process dragged on, however, many people got to know Xena and Gabrielle as the real names of these objects and are sad to see them change.