ERIS

Eris is the largest dwarf planet in our solar system and was originally given the provisional designation 2003 UB313. It was discovered in 2005 and is located in the scattered disk, a region of the outer Solar System. Eris is a trans-Neptunian object (TNO) and is a member of a group of similar objects known as the scattered disk.

Characteristics of Eris

• Size: Eris has a diameter of about 2,326 kilometers, making it slightly larger than Pluto.
• Orbit: Eris has a highly elliptical orbit, taking about 557 Earth years to complete one orbit around the Sun.
• Composition: Eris is composed primarily of rock and ice, similar to other dwarf planets in the outer solar system.
• Moons: Eris has one known moon, named Dysnomia, which is about 150 km in diameter.

Comparison with Pluto

Eris is often compared to Pluto due to its size and status as a dwarf planet. The discovery of Eris led to the reclassification of Pluto from a planet to a dwarf planet by the International Astronomical Union in 2006. Both Eris and Pluto are part of a group of objects known as "plutoids," which are dwarf planets that have an orbital semi-major axis greater than that of Neptune.

Study Guide for Eris

1. When was Eris discovered, and what was its original designation?
2. What region of the outer Solar System is Eris located in?
3. How does the size of Eris compare to that of Pluto?
4. What is the orbital period of Eris?
5. What is the name of Eris's moon, and how does its size compare to Eris?
6. How did the discovery of Eris impact the classification of Pluto?

These questions can help you understand the key characteristics and significance of Eris as a dwarf planet in our solar system.