... Molecular Cloud Barnard 68 . ... Where did all the stars go? What used to be considered a hole in the sky is now known to astronomers as a dark molecular cloud. Here, a high concentration of dust and molecular gas absorb practically all the visible light emitted from background stars. The Nebula And The Neutron Star . ... The apparently sparse cluster of stars just left of center in this composite color digital image, it is one of the smallest, faintest globular clusters known. ...