black hole
From Trekipedia
A black hole was a celestial object with a mass density so great that light could not escape it. Black holes could be formed when the core of a star collapsed in on itself after the outer layers exploded in a supernova: if the star's initial mass was greater than 8 stellar masses, the resulting neutron star's gravity would quickly cause it to collapse in upon itself until it became a black hole.[1]
