The new planet ERIS. What does ERIS mean? Why Eris?

Answer 1

Eris is not a planet, its the largest known dwarf planet in the solar system, between 2,400 and 3,000 kilometres in diameter and 27% more massive than Pluto.

The name comes from the Greek goddess Eris, a personification of strife and discord. The name was assigned on September 13, 2006 following an unusually long period in which it was known by the temporary name 2003 UB313, which was assigned automatically by the IAU under their naming protocols for minor planets.

Eris was discovered by the team of Mike Brown, Chad Trujillo, and David Rabinowitz on January 5, 2005.
The final name was delayed due to uncertainty over whether the object would be classified as a planet or a minor planet (naming rules are different for these 2 types of objects. The decision on a name had to wait until after the August 24, 2006 IAU ruling defining the object as a dwarf planet.

The team had previously thought that Persephone would be a good name for the object - however, once classified as a dwarf planet this name wasn't acceptable as there is already an asteroid with that name (399 Persephone).
IAU regulations require the name be from mythology for objects with orbital stability beyond Neptune's orbit.
The discovery team proposed 'Eris' on 6 September 2006 and it was accepted on 13 September 2006.

Answer 2

Eris was the Greek goddess of discord.

Why Eris? Because astronomers are still hung up on the pretentious notion that all celestial objects must be named after a Greek deity. This is despite the fact that very few of them are Greek.

This dwarf planet was originally named Xena, but the IAU felt that wasn't Greek enough.

Answer 3

Eris is the Greek goddess of discord. I suspect they picked this name because it fit with all the fuss about demoting Pluto from planet to something less than a planet after Eris, which is bigger than Pluto, was discovered.

Answer 4

For the name, see
http://astrogeology.usgs.gov/HotTopics/index.php?/archives/211-2003-UB313-named-Eris.html

It is a new "dwarf planet".

The discoverer (and NASA) had announced it as a 10th planet when it was discovered and announced (2003), but they are not the ones who decide such things.

The debate about whether Eris was a new planet is what eventually led to the demotion of Pluto.

Therefore, Eris may have been the right name to pick.

Answer 5

http://www.pantheon.org/articles/e/eris.html

Also according to the sources I just checked online, it is being called a dwarf planet or trans-Neptunian object and not a "planet" at this point. It is sort of in the same class that Pluto is now in as of last year.