The Coalsack Nebula is the most prominent dark nebula in the skies, being easily visible to the naked eye as a dark patch obscuring a brief section of Milky Way stars as they cross their southernmost region of the sky, east of Acrux which is the bright, southern pointer star of the southern cross. It dominates and overspills the southeast corner of what is considered the extent of the constellationCrux at a little less than twice the distance of Acrux, away from Earth.
General information
The Coalsack Nebula covers nearly 7° by 5° and overlaps somewhat into the neighbor constellations Centaurus and Musca. The first observation was reported by Vicente Yáñez Pinzón in 1499. It was named "il Canopo fosco" by Amerigo Vespucci and was also called "Macula Magellani" or "Black Magellanic Cloud" in opposition to the Magellanic Clouds. The Coalsack is omitted in most of today's standard catalogs on the Milky Way such as the New General Catalogue and its only mainstream identification number is in the somewhat specialist Caldwell catalogue, in which it is C99. , or the Southern Cross, and on the left is Scorpius. The head of the emu is the Coalsack. The Coalsack in Australian Aboriginal astronomy forms the head of the emu in the sky in several Aboriginal cultures. Amongst the Wardaman people, it is said to be the head and shoulders of a law-man watching the people to ensure they do not break traditional law. According to a legend reported by W. E. Harney, this being is called Utdjungon and only adherence to the tribal law by surviving tribe members could prevent him from destroying the world with a fiery star. There is also a reference by Gaiarbau regarding the coalsacks replicating bora rings on Earth. These astronomical sites allowed the spirits to continue ceremony similar to their human counterparts on Earth. As bora grounds are generally located on the compass points north/south, the southern coal sack indicates the initiation/ceremonial ring. In Inca astronomy this nebula was called Yutu, meaning a partridge-like southern bird or Tinamou.
In fiction
The Coalsack is mentioned in the ' episodes "The Immunity Syndrome |The Immunity Syndrome" and "Let That Be Your Last Battlefield", as well as ' by Arthur C. Clarke. In the Solar Queen series by Andre Norton, several characters swear "...by the Coalsack's Ripcord!" The Coalsack figures prominently in the Larry Niven and Jerry Pournelle's science fiction novelThe Mote in God's Eye and its sequels, The Gripping Hand and Outies. Also, Henry De Vere Stacpoole described the Coalsack in his novelThe Blue Lagoon, as Lestrange observes it from the deck of the Northumberland, "In the Milky Way, near the Southern Cross, occurs a terrible circular abyss, the Coal Sack. So sharply defined is it, so suggestive of a void and bottomless cavern, that the contemplation of it afflicts the imaginative mind with vertigo. To the naked eye it is as black and dismal as death, but the smallest telescope reveals it beautiful and populous with stars. Lestrange's eyes travelled from this mystery to the burning cross, and …" The Coalsack is mentioned in the Futurama episode "Hell Is Other Robots". In the film Night on the Galactic Railroad, the character Campanella ends going to the Coalsack. In the film The Chronicles of Riddick, the character Imam convinces Riddick to help his people against the Necromongers and says, "The Coalsack planets are gone." In Brian J. Clarke's novellaThe Expediter, a world of mysterious towers—and the aliens studying them—are found "behind the Coalsack". In the gameElite Dangerous players can visit the Coalsack Nebula. In The Star Kings by Edmond Hamilton Coalsack is the home of The League of Dark Worlds, most powerful military dictatorship in the Galaxy.
