Gallifrey is a fictional planet in the long-running British science fiction television series Doctor Who and is the homeworld of the Doctor and the Time Lords. It is supposed to be located in the constellation of Kasterborous, at "galactic coordinates ten-zero-eleven-zero-zero by zero-two from galactic zero centre" (Pyramids of Mars, 1975), some 250 million light years away from Earth (as stated in the 1996 Doctor Who television movie; this would put it outside our Milky Way galaxy, which is only 80-100 thousand light years in diameter).
During the first decade of the television series, the name of the Doctor's home planet was not revealed, although it was actually shown for the first time in The War Games (1969) during the Doctor's trial. It was finally identified by name for the first time in The Time Warrior (1973) whilst the Doctor was being interrogated by the Sontaran Commander Linx. The Third Doctor, at gun-point, informed Linx that he was aware of the Sontaran species. Linx, realising that if the Doctor were human he would have no knowledge of his species, asks, "What is your native planet?" The Doctor replies, "Gallifrey. I am a Time Lord."
It is never definitively stated when the appearances of Gallifrey in the television series take place. As the planet is often reached by means of time travel, its relative present could conceivably exist anywhere in the Earth's past or future.
Gallifrey's position in the revived series (2005 onwards) was filled in slowly over the first three years of the series' run. In Series 1, it had been implied that it was destroyed, along with the Dalek Empire, by the Doctor during the Time War. The planet was not referred to by name until the 2006 Christmas Special and wasn't shown on screen until "The Sound of Drums".
From space, Gallifrey is seen as a yellow-orange planet and is close enough to central space lanes for spacecraft to require clearance from Gallifreyan Space Traffic Control as they pass through its system. The planet is surrounded by a quantum force field as well as an impenetrable force field called the transduction barrier. This prevents all outsiders (with hostile intent, or otherwise) from approaching the planet and allows the Time Lords to maintain their status of absolute neutrality. It also lets them observe the actions of the rest of the Universe without actually taking part in its affairs. The barrier was breached on one occasion by the Sontarans, when it was sabotaged from within (The Invasion of Time, 1978).
The Doctor's granddaughter Susan described her home world (presumably Gallifrey, but not named as such) as having bright, silver-leafed trees and a burnt orange sky at night (The Sensorites, 1964), features that the Tenth Doctor reiterates in the episode "Gridlock" (2007). This casts an amber tint on anything outside the city, as seen in The Invasion of Time. Gallifrey's sky appeared blue and Earth-like in The Five Doctors (1983) within the isolated Death Zone, but this is likely a production oversight. This can be explained using what is stated in "The War Games" as the "Second Doctor" states the Time Lords can control their own environment, so the blue sky of the death zone could be an account of that.
In "Gridlock", the Doctor also mentions vast mountain ranges situated on Gallifrey, "with fields of deep red grass, capped with snow". He goes on to describe how Gallifrey's second sun would "rise in the south and the mountains would shine", with the silver-leafed trees looking like "a forest on fire" in the mornings. In "The Sound of Drums", the Doctor says that Gallifrey was called the "Shining World of the Seven Systems".
The Citadel of the Time Lords stands on the continent of Wild Endeavour, in the Mountains of Solace and Solitude ("The Sound of Drums"), where the Capitol is also located. Within the Capitol is the Panopticon, under which the Eye of Harmony, the nucleus of a black hole also used as the heart of the TARDIS. The Eye provides the power required for time travel (The Three Doctors, 1973; The Deadly Assassin, 1976), and all Time Lord TARDIS time machines draw their power from it (the 1996 television movie). Also situated in the Capitol is the Matrix, the vast extradimensional computer network which acts as the repository of all Time Lord knowledge as well as containing the memories of dead Time Lords (The Deadly Assassin).
Outside the city lie wastelands where "Outsiders", Gallifreyans who have dropped out of Time Lord society, live in less technological tribal communities. The wastes of Gallifrey include the Death Zone, an area that was used as a gladiatorial arena by the first Time Lords, pitting various species kidnapped from their respective time zones against each other (although Daleks and Cybermen were considered too dangerous to use). Inside the Death Zone stands the Tomb of Rassilon, the founder of Time Lord society (The Five Doctors).
Somewhere on Gallifrey is also a portal known as the Untempered Schism, a gap in the fabric of reality. Eight-year-old Gallifreyans are brought before the Schism and made to look into the Time Vortex as part of an initiation ceremony into the Time Lord Academy. According to the Doctor, some are inspired, some run away, and some are driven mad. ("The Sound of Drums").
In several spin-off novels, which are of uncertain canonicity, Gallifrey is said to have a copper moon, Pazithi Gallifreya (first named in Cat's Cradle: Time's Crucible). The novel Lungbarrow also places Karn (setting of The Brain of Morbius, 1976) in Gallifrey's solar system, along with a frozen gas giant named Polarfrey and an "astrological figure" of "Kasterborous the Fibster".
Subsequently, in "Dalek" (2005), it is revealed that the last great Time War was fought between the Time Lords and the Daleks, ending in the obliteration of both sides and with only two apparent survivors; the Doctor and a lone Dalek that had somehow fallen through time and crashed on Earth. At the conclusion of that episode, that surviving Dalek self-destructs, leaving the Doctor believing that he was the sole survivor of the Time War. However, the Daleks return in "Bad Wolf"/"The Parting of the Ways" (2005), and subsequently in "Army of Ghosts"/"Doomsday" (2006), "Daleks in Manhattan"/"Evolution of the Daleks" (2007), and "The Stolen Earth"/"Journey's End" (2008), the last of these being the series 4 finale where Davros also returns.
It is suggested that other Time Lords might have survived the war when the Face of Boe utters its final words to the Doctor: "Know this, Time Lord, you are not alone" ("Gridlock"). These suspicions are later borne out in "Utopia" (2007) when the Tenth Doctor discovers that the renegade Time Lord the Master has survived the Time War and has been living in human form in the year 100 trillion, at the end of the material universe, a point so far forward in time that it is believed that no Time Lord has ever travelled there.
The Doctor's reference to Gallifrey in "The Runaway Bride" marks the first time the name of his homeworld has been uttered on screen since the new series began. The Doctor's revelation that he is from Gallifrey elicits terror from the Empress of the Racnoss. John Smith (the Doctor in human form) also mentions Gallifrey in "Human Nature".
The planet makes its first appearance in the revived series in "The Sound of Drums", where the Citadel, enclosed in a glass globe (as described by the Doctor in "Gridlock"), is seen in flashback as the Doctor describes it. Also seen is a ceremony initiating 8-year-old Gallifreyans — in particular the Master — into the Time Lord Academy.
In the Eighth Doctor Adventures novel The Ancestor Cell by Peter Anghelides and Stephen Cole, Gallifrey is destroyed as a result of the Eighth Doctor's desire to prevent the voodoo cult Faction Paradox from starting a war between the Time Lords and an unnamed Enemy. This also apparently (and retroactively) wipes the Time Lords from history. It is unclear what the attitude of the new Doctor Who television series is toward the information in the novels and audio plays, the latter produced by Big Finish Productions. However, a number of writers of the novels and audio plays are also writing for the new television series, and Russell T Davies refers to the comic strips, audio plays and novels in an essay describing the Time War, written for the Doctor Who Annual 2006.
In the last regular Eighth Doctor novel, The Gallifrey Chronicles by Lance Parkin, it is revealed that while Gallifrey was destroyed, the Time Lords were not erased from history. However, the cataclysm sets up an event horizon in time that prevents anyone from entering Gallifrey's relative past or travelling from it to the present or future. The Time Lords also survive within the Matrix, which has been downloaded into the Eighth Doctor's mind, but their reconstruction requires a sufficiently advanced computer. At the novel's end, the question of whether or not the Time Lords will be restored remains unanswered, although if the events of the novel are to tie in with later events in the TV series it must be assumed that Gallifrey was at some point restored, only to be destroyed again during the events of the Time War.
Television series executive producer Russell T Davies wrote in Doctor Who Magazine #356 that there is no connection between the War of the books and the Time War of the television series. Presumably, if the novels and the television series events are to be reconciled, at some point Gallifrey is restored, only to be destroyed again in the Time War. In the same Doctor Who Magazine column, Davies compared Gallifrey being destroyed twice with Earth's two World Wars. He also said that he was "usually happy for old and new fans to invent the Complete History of the Doctor in their heads, completely free of the production team's hot and heavy hands".
Despite Davies' unequivocal statement that the two wars are distinct, Lance Parkin, in his Doctor Who chronology AHistory, suggests in a speculative essay that the two destructions of Gallifrey may be the same event seen from two different perspectives, with the Eighth Doctor present twice (and both times culpable for the planet's destruction).
In the Star Trek novel Ishmael, James T. Kirk refers to legends mentioning Gallifrey and the Time Lords. Another novel, The Doctor and the Enterprise (which features the Fourth Doctor appearing on the USS Enterprise) makes it clear that the Doctor is from another universe - in the normal Trek universe, Gallifrey no longer exists, as its sun went supernova eons ago and destroyed every planet in its system.