Mercury (planet)

Mercury was an inner planet in the solar system. The temperatures on Mercury were hot enough to melt lead and there was very little atmosphere.

Origin
By the reckoning of ArcHivist Farazea's 14 Planet Theory, Mercury initially formed as a double planet with what would become the Moon, Farazea observing that they were almost identical in composition and size. At some point, Mercury's twin was dislodged from its orbit and entered that of Earth, sending its own twin planet Mondas on a slow journey to the edge of the solar system. (AUDIO: Origins of the Cybermen)

Human era
Observing a temporary chronological disturbance based on a sudden instability in Sol in 1639 caused by the Eleven's stolen stellar manipulator, the Time Lords noted Sol I among the first three planets in the solar system to be in immediate danger. (AUDIO: The Satanic Mill)

Humans set up the Sunwatcher on Mercury to monitor the Sun. Powered by three solar pylons, it was a domed base that moved on tracks with the orbit of Mercury so that the base was always located at the optimum temperature. Three months after it was established, the base was staffed by five scientists. They encountered a native Mercurial who tried to warn the scientists of three "giants" that had attacked his people. At the same time, the Second Doctor arrived with Jamie McCrimmon and Zoe Heriot and, with his help, the Mercurials learned that the "giants" were the solar pylons. (PROSE: Mercury)

At one point, Mercury was used as a waste dump, but its orbit was accidentally destabilised and it plunged into the sun. (PROSE: To the Slaughter) The Eighth Doctor once claimed that Mercury had "very little atmosphere" after dumping a vampire on the planet. (AUDIO: Situation Vacant)

Later history
The Eleventh Doctor, with Amy Pond and Rory Williams, visited Mercury in the 367th century and witnessed the first contact between human miners and the native Mercurian energy beast. (COMIC: Hot Stuff!)

Undated events
When asked about her holiday experiences, Donna Noble listed Mercury among the locations which she had visited. (COMIC: The Widow's Curse)