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.

                               2023 January 29
   [2]A dark comma-shaped cloud appears in the middle of a dense field of
   stars. No stars are visible through the center of the cloud. Please see
               the explanation for more detailed information.

                      Barnard 68: Dark Molecular Cloud
          Image Credit: [3]FORS Team, [4]8.2-meter VLT Antu, [5]ESO

   Explanation: Where did all the stars go? What used to be considered a
   hole in the sky is now known to astronomers as a dark [6]molecular
   cloud. Here, a high concentration of [7]dust and [8]molecular gas
   absorb practically all the [9]visible light emitted from background
   stars. The eerily dark surroundings help make the interiors of
   [10]molecular clouds some of the coldest and most [11]isolated places
   in the universe. One of the most notable of these [12]dark absorption
   nebulae is a cloud toward the constellation [13]Ophiuchus known as
   [14]Barnard 68, [15]pictured here. That no stars are visible in the
   center indicates that [16]Barnard 68 is relatively nearby, with
   measurements placing it about 500 light-years away and half a
   [17]light-year across. It is [18]not known exactly how [19]molecular
   clouds like [20]Barnard 68 form, but it is known that these clouds are
   themselves [21]likely [22]places for [23]new stars to form. In fact,
   [24]Barnard 68 itself has [25]been found likely to collapse and form a
   new star system. It is possible to [26]look right through the cloud in
   [27]infrared light.

          Postcards from the Universe 2022: [28]APOD Year in Review
                Tomorrow's picture: bright marking on the sky
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    Authors & editors: [40]Robert Nemiroff ([41]MTU) & [42]Jerry Bonnell
                                 ([43]UMCP)
          NASA Official: Phillip Newman [44]Specific rights apply.
              [45]NASA Web Privacy Policy and Important Notices
                A service of: [46]ASD at [47]NASA / [48]GSFC,
                         [49]NASA Science Activation
                           & [50]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2301/barnard68v2_vlt_4000.jpg
   3. https://www.eso.org/sci/facilities/paranal/instruments/fors.html
   4. http://www.eso.org/projects/vlt/
   5. https://www.eso.org/
   6. https://en.wikipedia.org/wiki/Molecule
   7. https://apod.nasa.gov/apod/ap030706.html
   8. https://apod.nasa.gov/apod/ap970430.html
   9. https://science.nasa.gov/ems/09_visiblelight
  10. https://www.youtube.com/watch?v=YbdwTwB8jtc
  11. http://lh5.ggpht.com/__zoKJ77EvEc/TUunWxcWVlI/AAAAAAAAKyc/JW7UNzSdeS4/house-ellidaey5%5B2%5D.jpg
  12. https://apod.nasa.gov/apod/dark_nebulae.html
  13. https://en.wikipedia.org/wiki/Ophiuchus
  14. https://en.wikipedia.org/wiki/Barnard_68
  15. https://www.eso.org/public/news/eso0102/
  16. http://en.wikipedia.org/wiki/Edward_Emerson_Barnard
  17. http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question19.html
  18. https://i.ytimg.com/vi/9uuqXXT7VYo/hqdefault.jpg
  19. https://astronomy.swin.edu.au/cosmos/m/Molecular+Cloud
  20. https://www.eso.org/public/videos/eso9934a/
  21. https://apod.nasa.gov/apod/ap201206.html
  22. https://apod.nasa.gov/apod/ap221020.html
  23. https://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve
  24. https://ui.adsabs.harvard.edu/abs/2009ApJ...695.1308B/abstract
  25. http://www.universetoday.com/2009/06/09/astronomers-predict-birth-of-a-new-star/
  26. http://www.eso.org/public/news/eso9934/
  27. https://science.nasa.gov/ems/07_infraredwaves
  28. https://www.youtube.com/watch?v=HAk0ZUwG60s
  29. https://apod.nasa.gov/apod/ap230128.html
  30. https://apod.nasa.gov/apod/archivepix.html
  31. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  32. https://apod.nasa.gov/apod/lib/aptree.html
  33. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  34. https://apod.nasa.gov/apod/calendar/allyears.html
  35. https://apod.nasa.gov/apod.rss
  36. https://apod.nasa.gov/apod/lib/edlinks.html
  37. https://apod.nasa.gov/apod/lib/about_apod.html
  38. http://asterisk.apod.com/discuss_apod.php?date=230129
  39. https://apod.nasa.gov/apod/ap230130.html
  40. http://www.phy.mtu.edu/faculty/Nemiroff.html
  41. http://www.phy.mtu.edu/
  42. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  43. http://www.astro.umd.edu/
  44. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  45. https://www.nasa.gov/about/highlights/HP_Privacy.html
  46. https://astrophysics.gsfc.nasa.gov/
  47. https://www.nasa.gov/
  48. https://www.nasa.gov/centers/goddard/
  49. https://science.nasa.gov/learners
  50. http://www.mtu.edu/