Vulcan (Invasion of the Daleks)

Vulcan was the first planet out from Sol on the Daleks' chart of the solar system as they planned to invade in 2400. (COMIC: Invasion of the Daleks) However, others believed that Mercury was the first planet, (AUDIO: The Satanic Mill) making Earth "Sol III". (TV: Voyage of the Damned)

Vulcan appeared as an exhibit in the Museum of Things That Don't Exist. (PROSE: The Taking of Planet 5)

Behind the scenes

 * Scientists of the 19th and 20th centuries hypothesised the existence of a planet between the orbit of Mercury and Sol, and sometimes referred to that planet as Vulcan. This theory has since been discredited. The Vulcan in The Taking of Planet 5 is a reference to this.
 * David Whitaker, cowriter of Invasion of the Daleks, later penned The Power of the Daleks for television, in which the main setting is a planet Vulcan which has been partially colonised by humanity (consistent with the Golden Emperor's worries in Invasion of the Daleks that humanity will soon have colonies on all of the planets in the Solar System). The TV story does not, however, formally identify its Vulcan as belonging to the Solar System, making it unclear if it is the same as the earlier creation.