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 Daleks. (TV: The Stolen Earth)