Faraway dwarf planet
Eris is so distant that even powerful telescopes see it as a tiny point of light. It can travel much farther from the Sun than Pluto.
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Dwarf planet lesson
Eris
Dwarf planet
Eris is one of the most distant known dwarf planets and has a moon named Dysnomia.
Kid fact
Eris helped scientists rethink what counts as a planet.
Hubble view of Eris and Dysnomia
Location
Distant Kuiper Belt region
Kind
Dwarf planet
Moon
Dysnomia
Known for
Very distant orbit
Planet question
Finding Eris helped scientists decide how to define planets and dwarf planets, because it is similar in size to Pluto.
Dysnomia moon
Eris has a moon named Dysnomia. Watching the moon's orbit helps scientists learn Eris' mass.
Frozen surface
Eris is very cold. Methane frost may cover its surface, and its atmosphere, if present, would be extremely thin.
Look closely
The image is simple because Eris is so far away. Ask how scientists can learn so much from tiny points of light.
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