Eris, is the “largest dwarf planet known”. It was discovered in 2005 in a survey at California’s Palomar Observatory’s Samuel Oschin telescope by astronomers Mike Brown, Chad Trujillo, and David Rabinowitz.
Originally named UBU 313, or Xena as it was nicknamed, Eris received its current name on Setpmber 13, 2006. Eris is taken from Greek mythology. She was the goddess of warfare and is known to use jealously and envy to start wars. She is infamous for causing the Trojan war.
Fittingly, Eris’s satellite has been named Dysnomia, Dy for short. Dysnomia, in Greek mythology, is Eris’s daughter and the “demon spirit of lawlessness”. Dy takes “around two weeks to orbit its parent dwarf” who is about 8 times larger.
Eris lived up to its namesake by stirring up trouble in the astronomical community when a debate started over “its proper designation”. Larger than Pluto, back when Pluto still retained its planetary status, Eris called into question whether there should be ten planets with both included; nine, with Eris replacing Pluto; or eight, with neither being considered a full-fledged planet
The International Astronomical Union (IAU) met in Prague and at the end of their debate both Pluto and Eris were demoted to dwarf-planet status, leaving 8 planets in the solar system.
The designation dwarf planet simply put, means that Eris fulfills almost all the criteria for being a full planet, except “it doesn’t have the gravitational pull, because of its size, to clear space surrounding it of other celestial bodies. Eris has a diameter of 2400km, which is larger than Pluto, but significantly smaller than Earth’s which is 12,742km.
Eris is now “the largest object found in orbit around the sun since the discovery of Neptune and its moon Triton” in 1846. Along with Pluto, Eris is a member of the Kuiper belt, “a swarm of icy bodies beyond Neptune in orbit around the sun.
In addition, Eris is “the most distant object ever seen in orbit around the sun. Almost 10 billion miles from the sun, Eris is “3 times more distant than the next closets planet. It takes Eris almost years to orbit the sun.
Here, one can see a comparison of the dwarf planets Pluto, Eris, and Ceres.
And, here, one can see an image of Eris and its satellite Dy. This image was captured by the Hubble Space Telescope on August 30, 2006.
From its first sighting, Eris made an impact on the astronomical world. Named after the goddess of strife, Eris sparked a debate on what exactly qualified a planet as opposed to a dwarf-planet. Amidst this debate, Pluto was demoted to a dwarf-planet, a decision that shook the world. Now, Eris stands as the largest dwarf-planet known, but as astronomers are able to see further and further distances, it remains to be seen how long Eris will hold this position.