Light-year
A light-year was a unit of measurement used to measure interstellar distance. It was quantified as the distance that light travelled in a vacuum over the course of an Earth year. 100 light-years made up a light-century. (TV: The Ribos Operation [+]Loading...["The Ribos Operation (TV story)"])
Known distances
From Earth
Planet XXX was 9.2 light years from Earth. (AUDIO: Through the Ruins [+]Loading...["Through the Ruins (audio story)"])
Epsilon Eridani was "about 11 light-years or so" from Earth. (COMIC: Is Anyone There? [+]Loading...["Is Anyone There? (comic story)"])
Gliese 581d was 20 light-years from Earth. (TV: Smile [+]Loading...["Smile (TV story)"])
Vega 3 was 27 light-years from Earth. (PROSE: K9 and the Beasts of Vega [+]Loading...["K9 and the Beasts of Vega (novel)"])
Arcturus was 40 light-years from Earth. (PROSE: Only a Matter of Time [+]Loading...["Only a Matter of Time (short story)"])
Aldebaran II was 68 light-years from Earth. (AUDIO: The Paradise of Death [+]Loading...["The Paradise of Death (audio story)"])
Halcyon was 90 light-years from Earth. (AUDIO: The Resurrection of Mars [+]Loading...["The Resurrection of Mars (audio story)"])
Sunday was 100 light-years from Earth. (PROSE: Wetworld [+]Loading...["Wetworld (novel)"])
Beta Caprisis was 100 light-years from Earth. (PROSE: Sanctuary [+]Loading...["Sanctuary (novel)"])
In 1873, Mondas was 200 light-years from Earth. (AUDIO: The Silver Turk [+]Loading...["The Silver Turk (audio story)"])
Lucifer was 280 light-years from Earth. (PROSE: Lucifer Rising [+]Loading...["Lucifer Rising (novel)"])
Bellatrix was 324 light-years from Earth. (PROSE: Nightshade [+]Loading...["Nightshade (novel)"])
Gger was 500 light-years from Earth. (PROSE: Listen - The Stars [+]Loading...["Listen - The Stars (short story)"])
Crimson Heart was 10,000 light-years from Earth. (TV: Death of the Doctor [+]Loading...["Death of the Doctor (TV story)"])
The Orpheus constellation was 10,000 light-years from Earth. (TV: Aeolian [+]Loading...["Aeolian (TV story)"])
According to one account, Gallifrey was 30,000 light-years from Earth. (PROSE: The Devil Goblins from Neptune [+]Loading...["The Devil Goblins from Neptune (novel)"])
The homeworld of the Uvodni, located in the Spiral Cluster of the Dragon Nebula, was 34,000 light-years from Earth. (TV: Warriors of Kudlak [+]Loading...["Warriors of Kudlak (TV story)"])
New Earth was 50,000 light-years from Earth. (TV: Gridlock [+]Loading...["Gridlock (TV story)"])
Vandos was 60,000 light-years from Earth. (COMIC: Mr Nobody [+]Loading...["Mr Nobody (comic story)"])
Dæmos was 60,000 light-years from Earth. (TV: The Dæmons [+]Loading...["The Dæmons (TV story)"])
Galaxy Seven was 290,000 light-years from Earth. (PROSE: The Eyeless [+]Loading...["The Eyeless (novel)"])
Surobos was 420,000 light-years from Earth. (COMIC: Shipwreck! [+]Loading...["Shipwreck! (comic story)"])
Gorgos was 100,000,000 light-years from Earth. (TV: Eye of the Gorgon [+]Loading...["Eye of the Gorgon (TV story)"])
According to the Eighth Doctor, Gallifrey was 250,000,000 light-years from Earth. (TV: Doctor Who [+]Loading...["Doctor Who (TV story)"])
According to the Eleventh Doctor, Apalapucia was 2,000,000,000 light-years from Earth. (TV: The Girl Who Waited [+]Loading...["The Girl Who Waited (TV story)"])
According to the First Doctor, Destination was billions of light-years away from Earth. (AUDIO: The Destination Wars [+]Loading...["The Destination Wars (audio story)"])
From other locations
The Ao constellation and Qqaba were 9.6 light-years from Gallifrey. (PROSE: Lungbarrow [+]Loading...["Lungbarrow (novel)"])
Ribos was 300 light-years from the Magellanic Clouds. (TV: The Ribos Operation [+]Loading...["The Ribos Operation (TV story)"])
The Twelfth Cyber Legion was 20,000 light-years from Demons Run. (TV: A Good Man Goes to War [+]Loading...["A Good Man Goes to War (TV story)"])
Safeplace was about 32,000 light-years from Mars. (AUDIO: The Judgement of Isskar [+]Loading...["The Judgement of Isskar (audio story)"])
The First Doctor encountered a group of Watermen 5 million light-years from Q20. (COMIC: Dr. Who Meets the Watermen [+]Loading...["Dr. Who Meets the Watermen (comic story)"])
The Second Doctor once materialised the TARDIS while it was 4 quadrillion light-years from the nearest galaxy. (PROSE: When Starlight Grows Cold [+]Loading...["When Starlight Grows Cold (short story)"])
Katura was 3.62 light-years from Mars. (AUDIO: Judoon in Chains [+]Loading...["Judoon in Chains (audio story)"])
The blast on Hurala that destroyed the Exterminator during the Second Dalek War produced a flare visible from 7 light-years away. (PROSE: Prisoner of the Daleks [+]Loading...["Prisoner of the Daleks (novel)"])
Known measurements
The Mutter's Spiral galaxy was around 100,000 light-years in diameter. (PROSE: The Eyeless [+]Loading...["The Eyeless (novel)"]) Before splitting apart into an armada of asteroid spacecraft, the home planet of the Sycorax was located in the wastelands of the galaxy, many light years away from Earth. (PROSE: The Time Traveller's Almanac [+]Loading...["The Time Traveller's Almanac (reference book)"])
The Morestran empire spanned 80,000,000 light-years. (PROSE: Zeta Major [+]Loading...["Zeta Major (novel)"])
References
Rose Tyler once asked the Ninth Doctor what a lightyear was, to which he jokingly replied "a normal year, but with fewer calories". (PROSE: Knock! Knock! Who's There? [+]Loading...["Knock! Knock! Who's There? (novel)"])
