Wednesday, November 23, 2011

Dysnomia, a moon of the Kuiper belt object Eris, named after the spirit of lawlessness

Dysnomia is a moon of the Kuiper belt object (KBO) Eris. Dysnomia's discovery in 2005 significantly contributes to our understanding of the history and evolution of the solar system. By measuring the complete orbit of Dysnomia, going around Eris in about 16 days, it was possible to calculate that Eris has a mass 27 percent higher than that of Pluto [1-5].

In Greek mythology, Eris is the mother of Dysnomia, who represents the spirit (daimona) of lawlessness and poor civil constitution [6]. Considering that Eris is named after the Greek goddess of strife, discord, contention and rivalry (see second paragraph in KBO article), Neil deGrasse Tyson underlines the complicated social lives of classical gods and explains [3]:

One of Eris's pastimes was to instill jealousy and envy among men, driving them to battle. At the wedding of Peleus and Thetis, all the gods were invited with the exception of Eris. Angered by her exclusion, she vengefully instigated a quarrel among the goddesses that precipitated the Trojan War.
Brown [Mike Brown (Caltech), co-discoverer of Eris, who precisely calculated Eris to be 27 percent more massive than Pluto [2]] had indeed done his classical homework and dutifully captured Eris's destabilizing influence on the Pluto problem, causing a war of its own.

The latter war ended with the demotion of Pluto to the status of dwarf planet in 2006. Back to Dysnomia: with a mother like this, it should not come as a surprise that the offspring of dwarf planet Eris inherited ill spirits and soap-opera qualities. Astrophysically, the idea is favored that Dysnomia was born out of a collison between Eris and another KBO [5].

Keywords: astronomy, planetary science, solar system, celestial bodies, nomenclature, mythology, intrigue.

References, notes and more to explore
[1] M. E. Brown, M. A. van Dam, A. H. Bouchez, D. le Mignant, R. D. Campbell, J. C. Y. Chin, A. Conrad, S. K. Hartman, E. M. Johansson, R. E. Lafon, D. L. Rabinowitz, P. J. Stomski, Jr., D. M. Summers, C. A. Trujillo and P. L. Wizinowich: Satellites of the Largest Kuiper Belt Objects. The Astrophysical Journal March 1, 2006, 639, L43-L46 [].
Notice that in this publication Eris is stilled named by its original designation 2003 UB313 (see the second paragraph in my KBO post).
[2]  NASA > Solar System Exploration > Eris and Dysnomia:
[3] Neil deGrasse Tyson: The Pluto Files. W. W. Norton & Company, New York and London, 2009; pages 92 and 93.
[4] Dysnomia, the moon of Eris:
[5] Space Ref > Astronomers Measure Mass of Eris:
[6] Theoi Greek Mythology > Dysnomia:

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