Which planet is closest to the Sun ?
Ninth planet may refer to : Pluto , widely considered the ninth planet in the Solar System from 1930 until 2006 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