Stories tagged dwarf planet

Jun
20
2007

Demoted again: Pluto's ego took another blow this week when it was discovered that dwarf planet Eris is slightly bigger than the former "official" planet. (Drawing courtesy of NASA)
Demoted again: Pluto's ego took another blow this week when it was discovered that dwarf planet Eris is slightly bigger than the former "official" planet. (Drawing courtesy of NASA)
I guess you could call Pluto the Rodney Dangerfield of our solar system…it just doesn’t get any respect.

Last summer Pluto got demoted from an official planet in our solar system and placed in a new category of heavenly bodies: dwarf planets. Now with more research, it’s been determined that Pluto isn’t even among the largest of the dwarves.

Eris is the cause of all of this turmoil of Pluto’s status. That dwarf planet was discovered to have similarities to Pluto and led astronomers to relook at how they define planets. Pluto and Eris were both bumped into the dwarf plant status. Now, the size of Eris has been measured: a diameter of 1,490 to 1,860 miles. Pluto’s diameter is a shade smaller: 1,430 miles.

All of these details came to light after astronomers discovered a moon, Dysnomia, circling Eris. Judging from the speed that Dysonmia has spinning around Eris, researchers have determined that Eris is about 27 percent heavier than Pluto as well. Both dwarf planets are made up primarily of rock and ice.

Don’t worry about any physical effects from this growing dwarf planet rivalry. Eris’ orbit is about twice as far away from the sun as Pluto’s. They’re a quite safe distance apart from each other.

Sep
21
2006

Artist's concept of Eris.: Image courtsey NASA/JPL-Caltech.
Artist's concept of Eris.: Image courtsey NASA/JPL-Caltech.

The “Tenth Planet” that caused Pluto to lose its planetary status has been classified and named, and to the dismay of many, it was not named Xena. The International Astronomical Union has classified it as a dwarf planet and named it Eris, after the Greek goddess of Chaos, which is appropriate for the chaos it cause in the astronomical community over what should be defined a planet and what should not.

The debate centered around the argument that if Pluto was considered a planet, then 2003 UB313, as it was known at the time, should be a planet as well as it was larger than Pluto. The debate culminated at the International Astronomical Union meeting last month where Pluto was stripped of the title “planet” and relegated to “dwarf planet” along with Eris and the former asteroid Ceres.

Eris' moon was also given a formal name: Dysnomia. In Greek mythology Dysnomia was the daughter of Eris.