Coalsack Nebula
| Coalsack Nebula | |
|---|---|
 The Coalsack Nebula | |
| Observation data (Epoch J2000.0) | |
| Type | Dark |
| Right ascension | 12h 50m |
| Declination | −62° 30′ |
| Distance (ly) | 600 ly |
| Apparent magnitude (V) | – |
| Apparent dimensions (V) | 7 × 5 ° |
| Constellation | Crux |
| Physical characteristics | |
| Radius | 30–35 ly |
| Absolute magnitude (V) | – |
| Notable features | – |
| Other designations | C99 |
| See also: Dark nebula, Lists of nebulae | |
The Coalsack Dark Nebula (or simply the Coalsack) is the most prominent dark nebula in the skies, easily visible to the naked eye as a dark patch silhouetted against the southern Milky Way. It was known pre-historically in the Southern Hemisphere and was observed by Vicente Yáñez Pinzón in 1499. The Coalsack is located at a distance of approximately 600 light years away from Earth, in the constellation Crux.
General information
The Coalsack Dark Nebula covers nearly 7° by 5° and overlaps somewhat into the neighbour constellations Centaurus and Musca.[1] Although this nebula was known to the people of the Southern Hemisphere in prehistoric times,[2] its first observation was reported by Vicente Yáñez Pinzón in 1499. 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.
In 1970, Kalevi Mattila proved the Coalsack is not totally black. It has a very dim glow (10% of the brightness of the surrounding Milky Way), which comes from the reflection of the stars it obscures.
The Coalsack is not present in the New General Catalogue and in fact does not have an identification number (outside of the Caldwell Catalogue, in which it is C99).
The Coalsack is important in Australian Aboriginal astronomy, and 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.[3]
In Inca astronomy this nebula was called Yutu meaning a partridge-like southern bird[4] or Tinamou.[5]
In fiction
The Coalsack is mentioned in the Star Trek: The Original Series episodes The Immunity Syndrome;; and Let That Be Your Last Battlefield, as well as 2001: A Space Odyssey by Arthur C. Clarke.
In the Solar Queen series by Andre Norton, several characters swear "...by the Coalsack's Ripcord!"[6]
The Coalsack figures prominently in the Larry Niven and Jerry Pournelle's science fiction novel The Mote in God's Eye and its sequels, The Gripping Hand and Outies.[7]
Also, Henry De Vere Stacpoole described the Coalsack in his novel, The Blue Lagoon (1908), 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 …"[8]
Gallery
References
- ↑ Darling, David J. (2004). The universal book of astronomy: from the Andromeda Galaxy to the zone of avoidance. Hoboken, New Jersey: Wiley. p. 351. ISBN 0471265691.
- ↑ William F. Warren, Paradise found; the cradle of the human race at the North pole; a study of the prehistoric world, pp. 119-120.
- ↑ Songs of the Songmen, 28-30.
- ↑ p. 5, The Hundred Greatest Stars, James B. Kaler, New York, Copernicus Books, 2002.
- ↑ A.F. Aveni, ed. (2010). Archaeoastronomy in the New World : American primitive astronomy : proceedings of an international conference held at Oxford University, September, 1981. Cambridge: Cambridge University Press. ISBN 0521125472.
- ↑ http://www.gutenberg.org/files/16921/16921-h/16921-h.htm
- ↑ http://www.amazon.com/Outies-Mote-Gods-Eye-3/dp/0615434142/ref=sr_1_cc_1?s=movies-tv&ie=UTF8&qid=1318736760&sr=1-1-catcorr
- ↑ H. De Vere Stacpoole: ‘The Blue Lagoon’, London: Adelphi Terrace, 1908, T. Fisher Unwin Ltd., quote taken from 28th Impression (1923), p. 12, from pdf p. 28 at http://archive.org/details/bluelagoonromanc00stacrich
External links
- Starry Night Photography: Coalsack Dark Nebula
- Starry Night Photography: The Emu
- SIMBAD: Coal Sack Nebula
Coordinates: 
12h 52m 19s, −62° 25′ 28″
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