K37 Gem 5
From Tardis Wiki, the free Doctor Who reference
K37J5 is the designation of a Black Hole seen in The Impossible Planet, and The Satan Pit. Against all laws of Physics, A planet orbited it. The Doctor and Rose arrived in the TARDIS on a ship drilling through the planet looking for what is keeping it away from being sucked in. A Beast was trapped inside a 'pit' by an ancient race. The doctor eventually killed the beast, causing the planet to be sucked in, The Black Hole's current destination is unknown.
