Eleventh planet term "planet" was redefined to exclude the new category of dwarf planets (just as some planets had earlier been recategorised as asteroids). In 2006 Pluto, Eris, Haumea, Makemake, and (in the inner Solar System) the asteroid Ceres were reclassified as dwarf planets. Eleventh planet Eleventh planet (of the Solar System) may refer to Vesta, the eleventh object to be named a planet, later to be reclassified as an asteroid; Uranus, the eleventh planet from the Sun upon Vesta's discovery, though this was quickly superseded by new discoveries; or Haumea, which would be the eleventh planet if the classification advocated by
Ring system it now appears that Saturn's rings might be quite old, dating to the early days of the Solar System. Fainter planetary rings can form as a result of meteoroid impacts with moons orbiting around the planet or, in case of Saturn's E-ring, the ejecta of cryovolcanic material. The composition of ring particles varies; they may be silicate or icy dust. Larger rocks and boulders may also be present, and in 2007 tidal effects from eight 'moonlets' only a few hundred meters across were detected within Saturn's rings. The maximum size of a ring particle is determined by the specific strength