Eris

Eris is a fascinating dwarf planet located in the scattered disc, a region beyond the Kuiper Belt. It's one of the most massive objects in the Solar System, even more massive than Pluto.  

Key features of Eris:

• Size: Eris is roughly the same size as Pluto, with a diameter of about 2,326 kilometers.

• Orbit: Eris has a highly elliptical orbit, taking it far beyond the Kuiper Belt. Its perihelion (closest point to the Sun) is about 38 AU, while its aphelion (farthest point from the Sun) is over 97 AU.  

• Moon: Eris has one known moon, Dysnomia.  

• Surface: Eris's surface is covered in a layer of methane ice, which gives it a reddish-brown color.

• Extreme Cold: Due to its distance from the Sun, Eris is incredibly cold, with surface temperatures reaching as low as -243 degrees Celsius.  

The discovery of Eris played a significant role in the reclassification of Pluto as a dwarf planet.

It challenged the traditional definition of a planet and led to a new understanding of the outer Solar System.  

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