                        Astronomy Picture of the Day

    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

                         The Dark Tower in Scorpius
    Image Credit & Copyright: Data - Martin Pugh Processing - Rocco Sung

   Explanation: In silhouette against a crowded star field along the tail
   of the arachnalogical 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, a structure that spans almost 40 light-years across
   this gorgeous telescopic portrait. Known as a cometary globule, the
   swept-back cloud, is shaped by intense ultraviolet radiation from the
   OB association of very 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 hydrogen gas. Hot stars embedded in the dust
   can be seen as bluish 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: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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