Temple of Light
Deep inside the Onyx Nebula, the Temple of Light was the centre of an artificial world based around a light-giving source from a turret that housed a gleaming crystal that drew its energy from the nebula and converted it into light. After thousands of years, the crystal became cracked and ineffective. The Light Catcher (guardian of the Temple) had instigated a search for alternative power that had led to the draining of "real" sun's energies resulting in the loss of life on other worlds. The Eleventh Doctor managed to repair the crystal and the leaking energies were blocked restoring an endless means of extracting energy from the Onyx Nebula. (COMIC: The Light Catcher)