Island universe

An island universe, (PROSE: The Sons of the Crab ^[+]Loading...["The Sons of the Crab (short story)"], When Starlight Grows Cold ^[+]Loading...["When Starlight Grows Cold (short story)"]) or island-universe, (PROSE: The Claus-Rosen Bridge ^[+]Loading...["The Claus-Rosen Bridge (short story)"]) was a large self-contained region of stars.

The Doctor used the term "universe" interchangeably with "galaxy" (PROSE: The Sons of the Crab ^[+]Loading...["The Sons of the Crab (short story)"], When Starlight Grows Cold ^[+]Loading...["When Starlight Grows Cold (short story)"]) and sometimes used the full "island universe" term to distinguish them from "Space Time Universes", (PROSE: When Starlight Grows Cold ^[+]Loading...["When Starlight Grows Cold (short story)"]) but some accounts suggested that island-universes had more in common with universes, being separate realities. (PROSE: The Claus-Rosen Bridge ^[+]Loading...["The Claus-Rosen Bridge (short story)"])

Island universes included the Milky Way and the Crab Nebula. (PROSE: The Sons of the Crab ^[+]Loading...["The Sons of the Crab (short story)"]) Relative to the Milky Way, Skaro was located in the next universe but one. (PROSE: Doctor Who in an Exciting Adventure with the Daleks ^[+]Loading...["Doctor Who in an Exciting Adventure with the Daleks (novelisation)"], COMIC: The Road to Conflict ^[+]Loading...["The Road to Conflict (comic story)"])

The First Doctor once claimed that TARDIS had "carried [him] for many millions of light-years across the empty spaces between the island universes." (PROSE: The Sons of the Crab ^[+]Loading...["The Sons of the Crab (short story)"]) The Second Doctor once found himself in the empty spaces between island universes, discovering an ancient monstrous being which came from another island universe. (PROSE: When Starlight Grows Cold ^[+]Loading...["When Starlight Grows Cold (short story)"])

Dr. Who once claimed that TARDIS could go to "any planet in any universe". (TV: Daleks' Invasion Earth 2150 A.D. ^[+]Loading...["Daleks' Invasion Earth 2150 A.D. (theatrical film)"])

Behind the scenes

• "Island universes" used to be a common name for the observable points we now call galaxies. Originating from the writings of Immanuel Kant, the term was rooted in a belief that each island universe formed independently, expanding from their own Big Bangs. The nature of galaxies was the subject of the Great Debate.