Condensate Reefs
From Tardis Wiki, the free Doctor Who reference
The edge of the universe was located, according to the Fourteenth Doctor, beyond the Condensate Reefs and the Realm of the Boltzmann Brains. (TV: Wild Blue Yonder [+]Loading...["Wild Blue Yonder (TV story)"], PROSE: Wild Blue Yonder [+]Loading...["Wild Blue Yonder (novelisation)"])
