Fictional Planets of The Solar System - Vulcan

Vulcan was a hypothetical planet supposed to revolve around the Sun inside the orbit of Mercury, invoked to explain certain irregularities in Mercury's orbit. The planet was proposed as a hypothesis in 1859, and abandoned not later than 1915.

• Vulcan's Workshop (Astounding Stories, June 1932), short story by Harl Vincent: a penal colony is located on Vulcan.

• At the Center of Gravity (Astounding Stories, June 1936), short story by Ross Rocklynne: two individuals are trapped inside a hollow Vulcan.

• The Power of the Daleks (1966), serial in the Doctor Who TV series. Set on an Earth colony on Vulcan in the early 21st century, a world covered with swamps. Vulcan appears to be one of Earth's first colonies, set up by 2020 AD according to publicity, but it is unclear if it is in a nearby solar system, or if Vulcan is in the Solar System. Some fans speculate that it was a rogue planet which briefly drifted into the Earth system. Script directions refer to 'the Plutovian night', suggesting that the story was originally set on Pluto, or that Vulcan was in a similar orbit to Pluto, at the edge of the solar system.

The name "Vulcan" has been used for various other fictional planets, in and out of the Solar System, that do not correspond to the hypothetical planet Vulcan. The planet Vulcan in the Star Trek franchise, for instance, is specified as orbiting 40 Eridani A.