SOLAR SYSTEM

Detailed explanation-1: -Eris has a very small moon called Dysnomia.

Detailed explanation-2: -Reference Article: Facts about Eris, the first dwarf planet discovered. Eris was one of the first dwarf planets to be discovered in the solar system. It is almost the same size as Pluto, and its discovery directly led to the former ninth planet’s demotion.

Detailed explanation-3: -Eris does not clear out its orbit, so it did not meet one of the requirements. Consequently, it was placed in the newly created category of dwarf planet along with Pluto and Ceres, which also did not meet all of the requirements to be called a planet. Eris has one moon that we currently know about.