Astronomy Picture of the Day
Posted By admin On April 27, 2011 @ 11:18 am In Photo Essays | Comments Disabled
In silhouette against a crowded star field toward the constellation Scorpius, this dusty cosmic cloud evokes for some the image of an ominous dark tower. In fact, clumps of dust and molecular gas collapsing to form stars may well lurk within the dark nebula,
The Dark Tower in Scorpius
Credit & Copyright [1]: Don Goldman [2]
Explanation: In silhouette against a crowded star field toward the constellation Scorpius [3], this dusty cosmic cloud evokes for some the image of an ominous dark tower [4]. In fact, clumps of dust and molecular gas collapsing [5] to form stars may well lurk within the dark nebula, a structure that spans almost 40 light-years across this gorgeous telescopic portrait [6]. Known as a cometary globule [7], the swept-back cloud, extending from the lower right to the head (top of the tower) left and above center, is shaped by intense ultraviolet radiation from the OB association [8] of very hot stars in NGC 6231 [9], off the upper edge of the scene. That energetic ultraviolet light also powers the globule’s bordering reddish glow of hydrogen gas [10]. Hot stars embedded in the dust can be seen as bluish reflection nebulae [11]. This dark tower, NGC 6231, and [12] associated nebulae are about 5,000 light-years away.
Visit the NASA/JPL website to view more Astronomy Pictures of the Day [13]
Article printed from Recorder Online: http://www.berthoudrecorder.com
URL to article: http://www.berthoudrecorder.com/2011/04/27/astronomy-picture-of-the-day-63/
URLs in this post:
[1] Copyright: http://apod.nasa.gov/apod/lib/about_apod.html#srapply
[2] Don Goldman: http://dg-imaging.astrodon.com/
[3] Scorpius: http://hawastsoc.org/deepsky/sco/index.html
[4] ominous dark tower: http://poetry.eserver.org/childe-roland.html
[5] collapsing: http://archive.ncsa.uiuc.edu/Cyberia/Bima/StarForm.html
[6] gorgeous telescopic portrait: http://www.astrodonimaging.com/gallery/display.cfm?imgID=227
[7] cometary globule: http://apod.nasa.gov/apod/ap070806.html
[8] OB association: http://en.wikipedia.org/wiki/Stellar_association#Types
[9] NGC 6231: http://www.aao.gov.au/images/captions/aat072.html
[10] hydrogen gas: http://apod.nasa.gov/apod/ap051223.html
[11] reflection nebulae: http://apod.nasa.gov/apod/ap011228.html
[12] NGC 6231, and: http://panther-observatory.com/gallery/deepsky/doc/NGC6231_wide.htm
[13] Astronomy Pictures of the Day: http://antwrp.gsfc.nasa.gov/apod/
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