Eris I Dysnomia
Eris I Dysnomia, commonly referred to as Dysnomia, is the only moon of the dwarf planet Eris, which resides at the far reaches of our solar system. Eris itself is classified as a dwarf planet due to its inability to clear its orbital path despite having enough mass to maintain a nearly round shape. With a maximum distance from the sun of about 97.56 astronomical units, Eris is notably distant, and Dysnomia orbits it approximately every sixteen days. The moon is estimated to measure between 100 and 250 kilometers in diameter.
Eris was first discovered in 2003 by a team led by Michael E. Brown, and its moon was found shortly after, utilizing advanced observation techniques. The mass of Eris was determined to be around 28 percent greater than that of Pluto, sparking significant debate over the classification of celestial bodies in our solar system. This discussion ultimately resulted in the reclassification of Pluto as a dwarf planet, alongside Eris and a few others. The ongoing exploration of the Kuiper Belt suggests that many more dwarf planets may remain to be identified, highlighting the dynamic and evolving nature of our understanding of the solar system.
Eris I Dysnomia
FIELDS OF STUDY: Astronomy; Observational Astronomy; Space Technology
ABSTRACT: Eris I Dysnomia is the only moon of Eris, a dwarf planet on the edge of our solar system. Astronomers confirmed Eris’s existence in 2005 and at first considered Eris the tenth planet because it was larger than Pluto. The discovery of Eris sparked a debate as to what constitutes a planet. This controversy led to Pluto being demoted from planet to dwarf planet.
A Frigid World
According to the International Astronomical Union (IAU), a dwarf planet is a celestial body that (1) orbits the sun, (2) has enough mass to be round in shape, and (3) has not cleared the neighborhood around its orbit. A non-dwarf planet has a cleared orbit because its gravity is strong enough to either attract or push away smaller bodies in its path. Dwarf planets lack such gravity, so other objects may cross into their path. Most dwarf planets are in the Kuiper Belt, a region of the solar system beyond Neptune’s orbit.
Eris is a dwarf planet on the outer edge of our solar system, extremely far from the sun. It has a maximum distance from the sun of 97.56 astronomical units (AU), or 97.56 times the distance between Earth and the sun. Eris I Dysnomia, or simply Dysnomia, is its only moon. Dysnomia is estimated to be between 100 kilometers (62 miles) and 250 kilometers (155 miles) in diameter. Its orbit around Eris takes approximately sixteen days.
The IAU has recognized five dwarf planets: Pluto, Eris, Makemake, Haumea, and Ceres. Scientists believe that as many as six more dwarf planets could be recognized in the near future. They also speculate that as many as two hundred more may possibly exist in the Kuiper Belt.
The Great Planet Debate
Eris was first sighted in 2003 by a team of researchers led by Michael E. Brown, a professor of planetary science at the California Institute of Technology (CalTech). The team conducted additional observations and confirmed and announced the discovery in 2005. That year, Brown used a laser-guided adaptive optics system to discover Eris’s moon.
By observing the interactions between Eris and Dysnomia, astronomers were able to calculate the likely mass of Eris. They determined that Eris’s mass is about 28 percent greater than that of Pluto. This discovery initiated a debate about whether Eris should be considered the tenth planet of the solar system or whether Pluto should be considered a dwarf planet instead. In the end, Pluto was reclassified as a dwarf planet.
PRINCIPAL TERMS
- adaptive optics: a system installed on astronomical telescopes that allows astronomers to see celestial bodies that are very bright.
- dwarf planet: a celestial body that orbits the sun, has a nearly round shape, and has not cleared its orbital path of other celestial bodies.
- Eris: a dwarf planet on the edge of our solar system.
Bibliography
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"Eris: Overview." Solar System Exploration. Natl. Aeronautics and Space Administration, 15 Jan. 2015. Web. 9 Mar. 2015.
Peterson, Carolyn Collins. Astronomy 101. Avon: Adams, 2013. Print.
"Pluto and the Developing Landscape of Our Solar System." International Astronomical Union. IAU, n.d. Web. 9 Mar. 2015.
Redd, Nola Taylor. "Eris: The Dwarf Planet That Is Pluto’s Twin." Space.com. Purch, 27 Jan. 2015. Web. 9 Mar. 2015.