Coalsack Nebula

Coal Sack Nebula

The Coalsack Nebula (Southern Coalsack, or simply the Coalsack)<ref name="simbad">Template:Cite simbad</ref> is a dark nebula, which is visible to the naked eye as a dark patch obscuring part of the Milky Way east of Acrux (Alpha Crucis) in the constellation of Crux.<ref name="Franco2000">Template:Cite journal</ref>

General information

Historically any other dark cloud in the night sky was called coalsack. The Coalsack Nebula was juxtaposed in 1899 by Richard Hinckley Allen through naming the Northern Coalsack Nebula.<ref name="OMeara 2012">Template:Cite web</ref>

The Coalsack Nebula covers nearly 7° by 5° and extends into the neighboring constellations Centaurus and Musca.<ref>Template:Cite book</ref> The first observation was reported by Vicente Yáñez Pinzón in 1499.<ref name="ESO2009">Template:Cite web</ref> It was named "il Canopo fosco" (the dark Canopus) by Amerigo Vespucci and was also called "Macula Magellani" (Magellan's Spot) or "Black Magellanic Cloud" in opposition to the Magellanic Clouds.<ref name="ESO2009"/>

A depiction of the emu in the sky known as weitj. The weitj in the sky is male, and you can see them guarding their eggs. During Makuru (the coldest and wettest time of the year, that falls across June and July), which is an Australian Aboriginal constellation consisting of dark clouds rather than of stars. The European constellation on the right is Crux, or the Southern Cross, and on the left is Scorpius. The head of the emu is the Coalsack.

In Australian Aboriginal astronomy, the Coalsack 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.<ref>Songs of the Songmen, 28–30.</ref> There is also a reference by Gaiarbau (1880) 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 ceremonial ring.

In Inca astronomy this nebula was called Yutu, after a partridge-like South American bird,<ref>Template:Cite book</ref> or Tinamou.<ref>Template:Cite book</ref>

In popular culture

The Coalsack Nebula appeared in Kenji Miyazawa's story Night on the Galactic Railroad, where the protagonist, Giovanni, experiences his friend, Campanella, departing to his personal afterlife referred to as "True Heaven" where he sees his dead mother waiting for him. Giovanni is unable to see True Heaven, and is represented, instead, as the empty, black Coalsack to Giovanni.

The Coalsack Nebula and the galactic area surrounding it played a large role in Jerry Pournelle's CoDominium Universe, particularly The Mote in God's Eye and the sequel The Gripping Hand, both co-authored with Larry Niven. In these novels, a human-colonized system, New Caledonia, is on the opposite side of the Coalsack from Earth. Set against the Coalsack is a red supergiant, and between the supergiant and New Caledonia is a yellow F6 star, known as "The Mote in God's Eye".

External links

• Starry Night Photography: Coalsack Dark Nebula
• Starry Night Photography: The Emu
• SIMBAD: Coalsack Nebula