White hole

A white hole was the opposite of a black hole, where instead of sucking stuff in, it threw all kinds of stuff out. (COMIC: Sky Jacks) The Eleventh Doctor mentioned them while comparing it to the more mysterious grey hole. (COMIC: The Grey Hole)

An unnamed planet was protected from outsiders by white holes. (PROSE: Vanishing Point)

A white hole orbited the planet Albert, which emmitted a quantum field that made the planet sentient. The various species on the spaceship called the Bonaventure claimed a stake in the white hole. (PROSE: Grimm Reality)

For a time, a white hole existed in The Doctor's TARDIS, spitting out objects from the outside universe. (COMIC: Sky Jacks)