Planet (Bad Day in Tinseltown)

A frontier planet on the Outer Rim of the Mutter's Spiral was the location of the mining town Brightedge. A Cyber-Warship crashed there after experimenting with a phase shifter weapon.

When it was destroyed, the Seventh Doctor explained that it left a "scar in hyperpace," which resulted in a shortcut wormhole being created between the planet and the Inner Worlds. (AUDIO: Bad Day in Tinseltown)