Pluto couldtherefore exact a small measure of revenge, foritwas demoted from ninth planet to dwarf planet in 2006 partly dueto the discovery of Eris (and later Eris' moon Dysnomia). Get the Space ...

Close to 18 years ago, astronomers spotted a miniature, icy world named Eris billions of miles beyond Neptune. But unlike its dwarf planet cousin Pluto — which New Horizons promoted to a rich ...

Faraway Eris is Pluto's twin Date: October 26, 2011 Source: European Southern Observatory (ESO) Summary: Astronomers have measured the diameter of the dwarf planet Eris by catching it as it passed ...

Eris orbits the Sun three times as far out as Pluto, and up to 97 times as far out as the Earth. Owing to this great distance, measuring its size or detecting an atmosphere is difficult.

Dwarf planet Eris, similar in size to its better-known cosmic cousin Pluto, has remained an enigma since being discovered in 2005 lurking in the solar system's far reaches. While Pluto was ...

The dwarf planet formerly known as Xena received a new name Thursday, while Pluto was given a number to reflect the loss of its status as a planet. Michael E. Brown, a professor of planetary ...

But Eris is even farther-flung than Pluto, circling our star from about three times farther away. In November 2010, Eris passed in front of a faint background star from Earth's perspective.

Ex-planet Pluto just got a further demotion. Observations in 2005 had already revealed that it wasn’t the kingpin of the outer solar system: A more remote denizen called Eris has a diameter 5 ...

Eris’s close size to Pluto factored into the reassignment of Pluto into a dwarf planet. The moons of Eris and Pluto. You’d be reasonable to assume the two bodies are similar in composition too.

Eris is more massive than Pluto but has a smaller volume. It has only one known Moon, called Dysnomia, and it orbits the Sun in just over 559 years. At its closest approach, ...

The observations show that Eris is an almost perfect twin of Pluto in size and appears to be covered in a layer of ice. Results will be published in the Oct. 27 issue of the journal Nature.