Mutter ' s Spiral Mutter ' s Spiral was the Time Lord designation for the galaxy in which Earth ' s solar system was located . ( TV : " The Deadly Assassin " , et al . ) Human s knew Mutter ' s Spiral as the Milky Way or as Adric referred to it , Galaxia Kyklos . ( TV : " Four to Doomsday " ) By the time of Sabalom Glitz , it also went by the name of the Stellian Galaxy . ( TV : " The Mysterious Planet " ) At least one Gallifrey - based robot — K9 Mark II — recognised the galaxy both by the name " the Milky Way " and by " Mutter ' s Spiral " . ( WC : " Shada " ) During the War , it was also known as Mutter ' s Cluster . ( PROSE : " The Taking of Planet 5 " ) According to the Aubertide s , Mutter ' s Spiral was " in " the Stellarian Galaxy , with Gallifrey near the galaxy ' s core . ( PROSE : " Human Nature " ) Castellan Spandrell informed President Romana of a Fortean Flicker across the Stellarian Galaxy . It was traced to the planet Hogsumm . ( PROSE : " The Highest Science " , " Happy Endings " ) Mutter ' s Spiral was approximately one hundred thousand light - years in diameter . Its nearest significant neighbouring galaxy was the Andromeda Galaxy . It was also surrounded by several nearby minor satellite galaxies , such as Galaxy Seven , ( PROSE : " The Eyeless " ) and the two dwarf galaxies the Larger Magallenic Cloud and Smaller Magallenic Cloud . ( AUDIO : " The Last Voyage " ) The Doctor frequented Earth , a planet in Mutter ' s Spiral . ( TV : " An Unearthly Child " , et al . ) On one occasion , Earth was moved out of the galaxy to the Medusa Cascade by the Dalek s . ( TV : " The Stolen Earth " ) One of the Nine Gallifreys was first destroyed during the Battle of Mutter ' s Cluster . ( PROSE : " The Taking of Planet 5 " ) The Dalek Empire of the Seriphia Galaxy invaded this galaxy in the 42nd and 67th centuries . ( AUDIO : " Dalek Empire " ) Humanity was confined to Mutter ' s Spiral until the discovery of the intergalactic drive in the 54th century . ( AUDIO : " The Star Men " ) The Eighth Doctor recalled a saying in the Academy about how the beat of a butterfly ' s wing s in Mettula Orionsis caused a time storm in the Mutter ' s Spiral . ( AUDIO : " Storm Warning " ) Galactic trends . Oseidon had the highest radiation level in the galaxy . ( TV : " The Android Invasion " ) Binary vascular system s were not common in sentient species . ( PROSE : " Tragedy Day " ) The Tenth Doctor claimed human s were the only species in the galaxy to invent edible ball bearing s . ( TV : " Fear Her " ) There were no metamorph ic insectoid s in the Galactic vector containing the Mutter ' s Spiral . ( TV : " The Unicorn and the Wasp " ) Tivoli was the most conquered planet in this galaxy , leading to its inhabitants ( like Gibbis ) welcoming invasion and subjugation . ( TV : " The God Complex " ) Earth , however , was the most " invaded " planet , not only in the Mutter ' s Spiral but in four more galaxies . ( PROSE : " Borrowed Time " ) Xaos was said to be the oldest planet in the galaxy . ( COMIC : " The Warrior ' s Story " ) The Akoshemon system , and indeed its planets such as Akoshemon itself , were located right on the very edge of this galaxy , so much so that from Akoshemon ' s moon you could see the gap between this galaxy and its nearest one . ( PROSE : " Fear of the Dark " ) Planets and star systems . Mutter ' s Spiral had around 150 billion stars ( AUDIO : " The Apocalypse Element " ) and 100 billion habitable planets . ( PROSE : " Harvest of Time " ) Divisions . Mutter ' s Spiral was divided into four quadrants . In the Third Quadrant there were at least 8 , 023 sectors , with Sector 8023 containing Earth . ( TV : " Logopolis " ) Another sector was the Kappa Galanga sector , which contained the Lasron solar region . ( PROSE : " Prisoner of the Daleks " ) There were several galactic arms , including the Perseus arm where Mogar was located , ( TV : " Terror of the Vervoids " ) a western arm ( PROSE : " " ) and a secondary and tertiary arm . ( PROSE : " Burning Heart " ) Politics . There were several forms of galactic government . The Galactic Alliance was one governing body . ( TV : " From Raxacoricofallapatorius with Love " ) It was also under the dominion of the Shadow Proclamation . ( TV : " The Stolen Earth " ) At one point in their history , the Rutan Host controlled the whole Mutter ' s Spiral ; later the Sontaran s had driven them to the far fringes of the galaxy . ( TV : " Horror of Fang Rock " )