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reclassified as an asteroid; Uranus, the eleventh planet from the Sun upon Vesta's discovery, though this was quickly superseded by new discoveries; or Haumea, which would be the eleventh planet if the classification advocated by Alan Stern et al. were adopted; or Makemake, which would be the eleventh planet in terms of distance from the Sun, as opposed to order of discovery.

Summary

The eleventh planet in the early 19th century was Uranus by order of distance from the Sun, and Vesta in order of discovery. When Ceres (1801), Pallas (1802), Juno (1804) and Vesta (1807) were discovered in the 19th century, they were known as planets, and Neptune was not discovered until 1846, there were a total of eleven planets. At the time, even Uranus had been recognized as a planet for twenty years. However, the number of planets rapidly grew from 1850 onward, and Ceres, Pallas, Juno, and Vesta were re-classified as asteroids one, two, three, and four; the number of recognized planets dropped to eight until the discovery of Pluto in 1930.