The rings of Neptune were discovered in 1989 by the Voyager 2 spacecraft and are tenuous, faint and dusty, and resemble the rings of Jupiter more closely than those of Saturn or Uranus. Neptune possesses five known rings, each named for an astronomer who contributed important work on the planet: the Galle, Le Verrier, Lassell, Arago and Adams rings. Neptune also has a faint unnamed ring coincident with the orbit of Neptunian moon Galatea. The rings of Neptune are made of extremely dark material, likely organic compounds processed by radiation similar to that found in the rings of Uranus. The proportion of dust in the rings (between 20 and 70%) is high, while their optical depth is low, at less than 0.1. Uniquely, the Adams ring is divided into five discrete arcs, named Fraternité, Égalité 1 and 2, Liberté, and Courage. The arcs occupy a narrow range of orbital longitudes and are remarkably stable, having changed only slightly since their initial detection in 1980. How the arcs maintain stability is still under debate. However, their stability is probably related to the resonant interaction between the Adams ring and its inner shepherd moon, Galatea.
Read the rest of this article: <http://en.wikipedia.org/wiki/Rings_of_Neptune> _______________________________ Today's selected anniversaries: 1643: Thirty Years' War: The French led by Louis II de Bourbon, Prince de Condé scored a decisive victory against the Spanish in Rocroi, France. <http://en.wikipedia.org/wiki/Battle_of_Rocroi> 1780: A combination of thick smoke, fog, and heavy cloud cover caused complete darkness to fall on parts of Canada and the New England area of the United States, requiring candles to be used from noon until midnight. <http://en.wikipedia.org/wiki/New_England%27s_Dark_Day> 1802: Napoléon Bonaparte, First Consul of the French Republic, established the Légion d'honneur order as a reward to commend civilians and soldiers. <http://en.wikipedia.org/wiki/L%C3%A9gion_d%27honneur> 1848: Mexico ratified the Treaty of Guadalupe Hidalgo that was previously signed to end the Mexican–American War, officially ceding present-day California, Nevada, Utah, and other territory to the United States. <http://en.wikipedia.org/wiki/Mexican_Cession> 1919: Mustafa Kemal Atatürk traveled to Samsun to establish the Turkish National Movement to resist the partitioning of the Ottoman Empire after World War I, marking the start of the Turkish War of Independence. <http://en.wikipedia.org/wiki/Turkish_War_of_Independence> _____________________________ Wiktionary's word of the day: Ruritanian (adj): 1. Of or having the characteristics of a place full of adventure, romance, and intrigue, as in works of romantic fiction. 2. Used to describe a fictitious and generic foreign government or person, as used to state a general or hypothetical situation <http://en.wiktionary.org/wiki/Ruritanian> ___________________________ Wikiquote quote of the day: Humankind consists of two sexes, woman and man. Is it possible that a mass is improved by the improvement of only one part and the other ignored? Is it possible that if half of a mass is tied to earth with chains and the other half can soar into skies? --Mustafa Kemal Atatürk <http://en.wikiquote.org/wiki/Mustafa_Kemal_Atat%C3%BCrk> _______________________________________________ Wikipedia Daily Article mailing list. To unsubscribe, visit: https://lists.wikimedia.org/mailman/listinfo/daily-article-l Questions or comments? Contact [email protected]
