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
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    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/