Eris

Definition

Eris is a dwarf planet in the outer Solar System, and the most massive and second-largest known dwarf planet in the Solar System after Pluto. It is a significant object in the context of understanding the formation and evolution of our planetary system.

5 Must Know Facts For Your Next Test

1. Eris is the most massive and second-largest known dwarf planet in the Solar System, with a diameter slightly larger than that of Pluto.
2. Eris was discovered in 2005, and its discovery led to the reclassification of Pluto from a planet to a dwarf planet.
3. Eris orbits the Sun at an average distance of about 96 astronomical units (AU), which is approximately three times the distance from the Earth to the Sun.
4. The discovery of Eris and other large Kuiper Belt objects has helped astronomers better understand the formation and evolution of the Solar System.
5. Eris has a highly eccentric and inclined orbit, which suggests that it may have been influenced by the gravitational interactions with other objects in the Kuiper Belt.

Review Questions

• Explain how the discovery of Eris led to the reclassification of Pluto from a planet to a dwarf planet.
  • The discovery of Eris, which is slightly larger than Pluto, prompted astronomers to reconsider the definition of a planet. This led to the International Astronomical Union (IAU) establishing a new category of 'dwarf planet' in 2006, which includes Pluto and Eris. The IAU determined that for an object to be considered a planet, it must have cleared the area of its orbit of other objects, which Pluto and Eris had not done. This reclassification of Pluto was a significant event in the understanding of our Solar System's structure and the evolution of planetary definitions.
• Describe the significance of Eris in the context of the origin and evolution of the Solar System.
  • The discovery of Eris and other large Kuiper Belt objects has provided valuable insights into the formation and evolution of the Solar System. These distant, icy bodies are remnants of the original material that formed the planets, and their orbits and properties can help astronomers piece together the complex history of our planetary system. Eris, in particular, with its highly eccentric and inclined orbit, suggests that it may have been influenced by the gravitational interactions with other objects in the Kuiper Belt. Understanding these interactions can shed light on the dynamic processes that shaped the outer Solar System during its early stages.
• Analyze the relationship between Eris and the Kuiper Belt, and explain how this relationship contributes to our understanding of comets and related objects.
  • Eris is a member of the Kuiper Belt, a region of the Solar System beyond the orbit of Neptune that contains many small bodies and dwarf planets. The Kuiper Belt is considered the source of short-period comets, as the gravitational interactions between objects in this region can dislodge them from their orbits and send them towards the inner Solar System. Eris, as one of the largest and most massive Kuiper Belt objects, plays a role in shaping the dynamics of this region. By studying Eris and its interactions with other Kuiper Belt objects, astronomers can better understand the processes that lead to the formation and evolution of comets and related objects, which are important for understanding the early history and composition of the Solar System.

Related terms

Dwarf Planet: A celestial body that orbits the Sun, is large enough to be nearly round in shape, but has not cleared the area of its orbit of other objects and is not a satellite.

Kuiper Belt: A region of the Solar System beyond the orbit of Neptune, containing many small bodies and dwarf planets, including Eris.

Pluto: The largest and most massive dwarf planet in the Solar System, and the ninth-largest object directly orbiting the Sun.