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 26
    [2]The picture shows cometary globule CG4. Please see the explanation
                       for more detailed information.

                      CG4: A Ruptured Cometary Globule
        Image Credit & Copyright: [3]Nicolas Rolland & [4]Martin Pugh

   Explanation: Can a gas cloud grab a galaxy? It's not even close. The
   "claw" of this odd looking "creature" in the [5]featured photo is a gas
   cloud known as a [6]cometary globule. This globule, however, [7]has
   ruptured. Cometary [8]globules are typically characterized by [9]dusty
   heads and elongated [10]tails. These features cause cometary
   [11]globules to have visual similarities to [12]comets, but in reality
   they are very much different. [13]Globules are frequently the
   birthplaces of stars, and many show very young [14]stars in their
   heads. The reason for the rupture in the head of this object is not yet
   known. The [15]galaxy to the left of the globule is huge, very far in
   the distance, and only placed near [16]CG4 by [17]chance superposition.

                   Tomorrow's picture: wisp of star death
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    Authors & editors: [29]Robert Nemiroff ([30]MTU) & [31]Jerry Bonnell
                                 ([32]UMCP)
          NASA Official: Phillip Newman [33]Specific rights apply.
              [34]NASA Web Privacy Policy and Important Notices
                A service of: [35]ASD at [36]NASA / [37]GSFC
                           & [38]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2107/CG4_Rolland_4000.jpg
   3. https://www.flickr.com/photos/nicolasrollandastro/
   4. https://www.martinpughastrophotography.space/
   5. https://www.astrobin.com/full/oa9ky4/0/
   6. https://en.wikipedia.org/wiki/cometary_globule
   7. https://ui.adsabs.harvard.edu/abs/1995A&A...293..493G/abstract
   8. https://apod.nasa.gov/apod/ap020325.html
   9. https://apod.nasa.gov/apod/lib/glossary.html#dust
  10. https://ui.adsabs.harvard.edu/abs/1996ApJ...463L.105M/abstract
  11. https://apod.nasa.gov/apod/ap140414.html
  12. https://apod.nasa.gov/apod/ap170409.html
  13. https://en.wikipedia.org/wiki/Dark_nebula
  14. https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve
  15. http://en.wikipedia.org/wiki/Galaxy
  16. https://en.wikipedia.org/wiki/CG_4
  17. https://blogmais.files.wordpress.com/2008/04/imagem_ht_07-04-23.jpg
  18. https://apod.nasa.gov/apod/ap210725.html
  19. https://apod.nasa.gov/apod/archivepix.html
  20. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  21. https://apod.nasa.gov/apod/lib/aptree.html
  22. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  23. https://apod.nasa.gov/apod/calendar/allyears.html
  24. https://apod.nasa.gov/apod.rss
  25. https://apod.nasa.gov/apod/lib/edlinks.html
  26. https://apod.nasa.gov/apod/lib/about_apod.html
  27. http://asterisk.apod.com/discuss_apod.php?date=210726
  28. https://apod.nasa.gov/apod/ap210727.html
  29. http://www.phy.mtu.edu/faculty/Nemiroff.html
  30. http://www.phy.mtu.edu/
  31. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  32. http://www.astro.umd.edu/
  33. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  34. https://www.nasa.gov/about/highlights/HP_Privacy.html
  35. https://astrophysics.gsfc.nasa.gov/
  36. https://www.nasa.gov/
  37. https://www.nasa.gov/centers/goddard/
  38. http://www.mtu.edu/