What used to be considered holes in the sky is now known to astronomers as dark molecular clouds. One of the most notable of these dark absorption nebulae is a cloud toward the constellation Ophiuchus known as Barnard 68 where a high concentration of dust and molecular gas absorb practically all the visible light emitted from background stars. The eerily dark interiors of molecular clouds are some of the coldest and most isolated places in the universe. It is not known exactly how molecular clouds like Barnard 68 form, but it is known that these clouds are themselves likely places for new stars to be born. In fact, Barnard 68 will probably collapse and form a new star system.
Image Credit: ESO