NEBULAE & STAR CLUSTERS A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site dark nebula Van den Bergh 142. Image courtesy Richard Crisp A relatively dense (up to 104 particles/cm3) interstellar cloud of matter whose dust particles obscure the light from stars or bright nebulae beyond it and give the cloud the appearance of a starless region. Such nebulae have the appearance of holes in the sky. They range in size from globules, a few thousand astronomical units across, to sprawling regions of starless darkness such as the Coalsack. Also known as an absorption nebula. Related category    • NEBULAE AND STAR CLUSTERS Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP