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Affichage des articles dont le libellé est Eris (dwarf planet)news. Afficher tous les articles
Affichage des articles dont le libellé est Eris (dwarf planet)news. Afficher tous les articles

mardi 28 juillet 2020

Eris (dwarf planet)

Eris (dwarf planet).
Eris is the second-largest known dwarf planet in the Solar System, slightly smaller by volume than the dwarf planet Pluto, although it is 27 percent more massive. Discovered in January 2005 by a team based at Palomar Observatory, it was named after Eris, the Greek goddess of strife and discord. The ninth-most-massive object directly orbiting the Sun, Eris is the largest object in the Solar System that has not been visited by a spacecraft. It is a member of a high-eccentricity population known as the scattered disk and has one known moon, Dysnomia. It is about 96 astronomical units (14.4 billion kilometres; 8.9 billion miles) from the Sun, roughly three times as far away as Pluto. Except for some long-period comets, Eris and Dysnomia were the most distant known natural objects in the Solar System until 2018 VG18 was discovered in 2018. Observations of a stellar occultation by Eris in 2010 showed that its diameter was 2,326 ± 12 kilometers (1,445.3 ± 7.5 mi).