Dysnomia (moon)

[[File:Hubble Dysnomia orbit overlay.jpg

Dysnomia is a moon orbiting the dwarf planet Eris, one of the largest known dwarf planets in the Solar System. Discovered in 2005 by a team led by Mike Brown, Dysnomia has garnered interest for its role in understanding the dynamics of distant celestial bodies in the Kuiper Belt, a region of the Solar System beyond the orbit of Neptune filled with numerous small bodies and dwarf planets.

Discovery and Naming

Dysnomia was discovered after observations made with the Keck Observatory in Hawaii. Its discovery was instrumental in the reclassification of Eris and the definition of the term "dwarf planet" by the International Astronomical Union (IAU) in 2006. The moon is named after Dysnomia, the daughter of the Greek goddess Eris, in keeping with the naming convention of naming moons after characters associated with the primary body's namesake. The name Dysnomia also reflects the theme of discord and strife, consistent with the controversy over the classification of Eris and the redefinition of planetary status that led to Pluto's demotion to a dwarf planet.

Physical Characteristics

Dysnomia is significantly smaller than Eris, which is one of the most massive objects in the Kuiper Belt. The exact size of Dysnomia is difficult to determine due to its distant location and small size, but it is believed to be a fraction of the size of Eris. Observations suggest that Dysnomia reflects about half the light that Eris does, which could indicate a difference in surface materials or composition between the two bodies.

Orbit

Dysnomia orbits Eris at a distance that allows it to complete an orbit in about 16 days. This relatively close orbit suggests that Dysnomia may have formed from debris resulting from a collision or from the gravitational capture of a passing body by Eris. The dynamics of the orbit provide valuable insights into the formation and evolution of binary systems in the Kuiper Belt.

Significance

The discovery of Dysnomia played a key role in the debate over the definition of a planet. The presence of a moon around Eris provided crucial evidence of Eris's mass, which was found to be comparable to that of Pluto. This discovery contributed to the IAU's decision to create a new category of celestial bodies known as dwarf planets, which includes Eris, Pluto, and several other objects in the Solar System.

Exploration

As of now, there have been no space missions to Dysnomia or Eris. However, the study of these distant celestial bodies continues to be a priority for astronomers. Future missions to the Kuiper Belt could provide more detailed information about Dysnomia's composition, orbit, and the nature of its relationship with Eris.

See Also

• Eris
• Kuiper Belt
• Dwarf planet
• List of natural satellites