Part of the Coalsack Nebula
The Coalsack Nebula in the constellation of Crux
Wide-field view of part of the Coalsack Nebula
Videos
Part of the Coalsack Nebula (fulldome)
Part of the Coalsack Nebula in close-up
Dark smudges almost block out a rich star
field in this new image captured by the Wide Field Imager camera,
installed on the MPG/ESO 2.2-metre telescope at ESO’s La Silla
Observatory in Chile. The inky areas are small parts of a huge dark
nebula known as the Coalsack, one of the most prominent objects of its
kind visible to the unaided eye. Millions of years from now, chunks of
the Coalsack will ignite, rather like its fossil fuel namesake, with the
glow of many young stars.
The Coalsack Nebula is located about 600 light-years away in the constellation of Crux
(The Southern Cross). This huge, dusky object forms a conspicuous
silhouette against the bright, starry band of the Milky Way and for this
reason the nebula has been known to people in the southern hemisphere
for as long as our species has existed.
The Spanish explorer Vicente Yáñez Pinzón first reported the
existence of the Coalsack Nebula to Europe in 1499. The Coalsack later
garnered the nickname of the Black Magellanic Cloud, a play on its dark
appearance compared to the bright glow of the two Magellanic Clouds,
which are in fact satellite galaxies of the Milky Way. These two bright
galaxies are clearly visible in the southern sky and came to the
attention of Europeans during Ferdinand Magellan’s explorations in the
16th century. However, the Coalsack is not a galaxy. Like other dark
nebulae, it is actually an interstellar cloud of dust so thick that it
prevents most of the background starlight from reaching observers.
A significant number of the dust particles in dark nebulae have coats
of frozen water, nitrogen, carbon monoxide and other simple organic
molecules. The resulting grains largely prevent visible light from
passing through the cosmic cloud. To get a sense of how truly dark the
Coalsack is, back in 1970, the Finnish astronomer Kalevi Mattila
published a study estimating that the Coalsack has only about 10 percent
of the brightness of the encompassing Milky Way. A little bit of
background starlight, however, still manages to get through the
Coalsack, as is evident in the new ESO image and in other observations
made by modern telescopes.
The little light that does make it through the nebula does not come
out the other side unchanged. The light we see in this image looks
redder than it ordinarily would. This is because the dust in dark
nebulae absorbs and scatters blue light from stars more than red light,
tinting the stars several shades more crimson than they would otherwise
be.
Millions of years in the future the Coalsack’s dark days will come to
an end. Thick interstellar clouds like the Coalsack contain lots of
dust and gas — the fuel for new stars. As the stray material in the
Coalsack coalesces under the mutual attraction of gravity, stars will
eventually light up, and the coal “nuggets” in the Coalsack will
"combust", almost as if touched by a flame.
More Information
ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.
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Contacts
Richard Hook
ESO education and Public Outreach Department
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
ESO education and Public Outreach Department
Garching bei München, Germany
Tel: +49 89 3200 6655
Cell: +49 151 1537 3591
Email: rhook@eso.org
Source: ESO
