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 November 3
   [2]The picture shows a deep image of the part of the Orion Nebula that
      features both the Horsehead Nebula and the Flame Nebula. Detailed
   surrounding dust and stars are also visible. Please see the explanation
                       for more detailed information.

                       The Horsehead and Flame Nebulas
                  Image Credit & Copyright: [3]Wissam Ayoub

   Explanation: The [4]Horsehead Nebula is one of the most famous nebulae
   on the sky. It is visible as the dark indentation to the orange
   [5]emission nebula at the far right of the [6]featured picture. The
   [7]horse-head feature is dark because it is really an opaque [8]dust
   cloud that lies in front of the bright [9]emission nebula. Like clouds
   in [10]Earth's atmosphere, this cosmic cloud has assumed a
   [11]recognizable shape by chance. After [12]many thousands of years,
   the internal motions of the cloud will surely alter its appearance. The
   emission [13]nebula's orange color is caused by [14]electrons
   recombining with [15]protons to form [16]hydrogen atoms. Toward the
   lower left of the image is the [17]Flame Nebula, an orange-tinged
   nebula that also contains intricate filaments of dark dust. Two
   prominent [18]reflection nebulas are visible: round [19]IC 432 on the
   far left, and [20]blue [21]NGC 2023 just to the lower left of the
   Horsehead nebula. Each glows primarily by [22]reflecting the light of
   their central star.

    Discovery + Outreach: [23]Graduate student research position open for
                                    APOD
                       Tomorrow's picture: open space
     __________________________________________________________________

      [24]< | [25]Archive | [26]Submissions | [27]Index | [28]Search |
   [29]Calendar | [30]RSS | [31]Education | [32]About APOD | [33]Discuss |
                                    [34]>
     __________________________________________________________________

    Authors & editors: [35]Robert Nemiroff ([36]MTU) & [37]Jerry Bonnell
                                 ([38]UMCP)
          NASA Official: Phillip Newman [39]Specific rights apply.
              [40]NASA Web Privacy Policy and Important Notices
                A service of: [41]ASD at [42]NASA / [43]GSFC
                           & [44]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2111/HorseFlame_Ayoub_4305.jpg
   3. https://www.astrobin.com/users/Wissam_Astrophotography/
   4. https://en.wikipedia.org/wiki/Horsehead_nebula
   5. https://apod.nasa.gov/apod/emission_nebulae.html
   6. https://www.astrobin.com/biwuli/0/
   7. https://apod.nasa.gov/apod/ap140728.html
   8. https://apod.nasa.gov/apod/ap030706.html
   9. https://en.wikipedia.org/wiki/Emission_nebula
  10. http://www.nasa.gov/mission_pages/sunearth/science/atmosphere-layers2.html
  11. http://www.brucevanpatter.com/cloudshapes.html
  12. https://cdn.shopify.com/s/files/1/0272/4770/6214/articles/do-cats-get-bored-800x533.jpg
  13. https://apod.nasa.gov/apod/ap061015.html
  14. https://history.aip.org/exhibits/electron/
  15. https://home.cern/news/news/physics/proton-century
  16. https://periodic.lanl.gov/1.shtml
  17. https://apod.nasa.gov/apod/ap210412.html
  18. https://apod.nasa.gov/apod/reflection_nebulae.html
  19. https://telescopius.com/deep-sky/object/606/ic-432/bright-nebula
  20. https://spaceplace.nasa.gov/blue-sky/en/
  21. https://apod.nasa.gov/apod/ap180329.html
  22. https://apod.nasa.gov/apod/ap070611.html
  23. https://asterisk.apod.com/viewtopic.php?f=28&t=41989
  24. https://apod.nasa.gov/apod/ap211102.html
  25. https://apod.nasa.gov/apod/archivepix.html
  26. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  27. https://apod.nasa.gov/apod/lib/aptree.html
  28. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  29. https://apod.nasa.gov/apod/calendar/allyears.html
  30. https://apod.nasa.gov/apod.rss
  31. https://apod.nasa.gov/apod/lib/edlinks.html
  32. https://apod.nasa.gov/apod/lib/about_apod.html
  33. http://asterisk.apod.com/discuss_apod.php?date=211103
  34. https://apod.nasa.gov/apod/ap211104.html
  35. http://www.phy.mtu.edu/faculty/Nemiroff.html
  36. http://www.phy.mtu.edu/
  37. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  38. http://www.astro.umd.edu/
  39. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  40. https://www.nasa.gov/about/highlights/HP_Privacy.html
  41. https://astrophysics.gsfc.nasa.gov/
  42. https://www.nasa.gov/
  43. https://www.nasa.gov/centers/goddard/
  44. http://www.mtu.edu/