Ninth planet (disambiguation)

Ninth planet may refer to:

Pluto, considered to be the ninth planet from its discovery in 1930 until its reclassification as a dwarf planet in 2006; still considered a planet by some scientists
Neptune, the ninth-closest planet from the Sun from 1979 to 1999 (with Pluto then considered the eighth-closest planet from the Sun)
The asteroid 2 Pallas, considered to be the ninth planet in chronological discovery order from 1802 until its reclassification as a minor planet in the 1850s
Jupiter, considered the ninth-closest planet from the Sun from 1807 to 1845 as a result of the discovery of minor planets
Planet X, various hypothetical planets beyond Neptune

See also