Astronomy Picture of the Day [1]Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2021 July 15 [2]See Explanation. Clicking on the picture will download the highest resolution version available. The Dark Tower in Scorpius Image Credit & [3]Copyright: Data - [4]Martin Pugh Processing - [5]Rocco Sung Explanation: In silhouette against a crowded star field along the tail of the arachnalogical constellation [6]Scorpius, this dusty cosmic cloud evokes for some the image of an [7]ominous dark tower. In fact, clumps of dust and molecular gas [8]collapsing to form stars may well lurk within the dark nebula, a structure that spans almost 40 light-years across this [9]gorgeous telescopic portrait. Known as a [10]cometary globule, the swept-back cloud, is shaped by intense ultraviolet radiation from the [11]OB association of very [12]hot stars in NGC 6231, off the upper edge of the scene. That energetic ultraviolet light also powers the globule's bordering reddish glow of [13]hydrogen gas. Hot stars embedded in the dust can be seen as bluish [14]reflection nebulae. This dark tower, NGC 6231, and associated nebulae are about 5,000 light-years away. Tomorrow's picture: pixels in space __________________________________________________________________ [15]< | [16]Archive | [17]Submissions | [18]Index | [19]Search | [20]Calendar | [21]RSS | [22]Education | [23]About APOD | [24]Discuss | [25]> __________________________________________________________________ Authors & editors: [26]Robert Nemiroff ([27]MTU) & [28]Jerry Bonnell ([29]UMCP) NASA Official: Phillip Newman [30]Specific rights apply. [31]NASA Web Privacy Policy and Important Notices A service of: [32]ASD at [33]NASA / [34]GSFC & [35]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2107/Dark_Tower_MPRS.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://www.martinpughastrophotography.space/about 5. https://www.facebook.com/sungcs/ 6. http://hawastsoc.org/deepsky/sco/index.html 7. https://en.wikipedia.org/wiki/Childe_Roland_to_the_Dark_Tower_Came 8. https://apod.nasa.gov/apod/ap210630.html 9. https://www.astrobin.com/gcvdk7/ 10. https://apod.nasa.gov/apod/ap070806.html 11. http://en.wikipedia.org/wiki/Stellar_association#Types 12. https://chandra.harvard.edu/photo/2018/ngc6231/index.html 13. https://apod.nasa.gov/apod/ap051223.html 14. https://apod.nasa.gov/apod/ap011228.html 15. https://apod.nasa.gov/apod/ap210714.html 16. https://apod.nasa.gov/apod/archivepix.html 17. https://apod.nasa.gov/apod/lib/apsubmit2015.html 18. https://apod.nasa.gov/apod/lib/aptree.html 19. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 20. https://apod.nasa.gov/apod/calendar/allyears.html 21. https://apod.nasa.gov/apod.rss 22. https://apod.nasa.gov/apod/lib/edlinks.html 23. https://apod.nasa.gov/apod/lib/about_apod.html 24. http://asterisk.apod.com/discuss_apod.php?date=210715 25. https://apod.nasa.gov/apod/ap210716.html 26. http://www.phy.mtu.edu/faculty/Nemiroff.html 27. http://www.phy.mtu.edu/ 28. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 29. http://www.astro.umd.edu/ 30. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 31. https://www.nasa.gov/about/highlights/HP_Privacy.html 32. https://astrophysics.gsfc.nasa.gov/ 33. https://www.nasa.gov/ 34. https://www.nasa.gov/centers/goddard/ 35. http://www.mtu.edu/