Asteroid: Difference between revisions
== Discovery ==
[[Image:243 ida.jpg|thumb|right|[[243 Ida]] and its moon Dactyl
The first named minor planet, [[Ceres (dwarf planet)|Ceres]], was discovered in 1801 by [[Giuseppe Piazzi]], and was originally considered a new planet.<ref group=note>Ceres, originally considered a new planet, is the largest main belt object and is now classified as a [[dwarf planet]]. All other asteroids are now classified as [[Small Solar System body|small solar system bodies]] along with comets, centaurs, and the smaller TNOs.</ref> This was followed by the discovery of other similar bodies, which with the equipment of the time appeared to be points of light, like stars, showing little or no planetary disc (though readily distinguishable from stars due to their apparent motions). This prompted the astronomer [[William Herschel|Sir William Herschel]] to propose the term "asteroid", from Greek ''αστεροειδής'', ''asteroeidēs'' = star-like, star-shaped, from ancient Greek ''Aστήρ'', ''astēr'' = star. In the early second half of the nineteenth century, the terms "asteroid" and "planet" (not always qualified as "minor") were still used interchangeably; for example, the [http://books.google.ca/books?id=NAMAAAAAMAAJ&pg=PA316&dq=%22planets%22+asteroids ''Annual of Scientific Discovery for 1871''], page 316, reads "Professor J. Watson has been awarded by the Paris Academy of Sciences, the astronomical prize, Lalande foundation, for the discovery of 8 new asteroids in one year. The planet Lydia (No. 110), discovered by M. Borelly at the Marseilles Observatory [...] M. Borelly had previously discovered 2 planets bearing the numbers 91 and 99 in the system of asteroids revolving between Mars and Jupiter" (emphasis added).