Dark Clouds of the Carina Nebula . ... Credit Copyright: NASA , ESA , N. Smith ( U. California, Berkeley ) et al. , and The Hubble Heritage Team ( STScI / AURA ) Explanation: What dark forms lurk in the mists of the Carina Nebula? These ominous figures are actually molecular clouds , knots of molecular gas and dust so thick they have become opaque . ... Pictured above is part of the most detailed image of the Carina Nebula ever taken, a part where dark molecular clouds are particularly prominent. ...