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.

                                2022 March 25
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                              The Medusa Nebula
               Image Credit & [3]Copyright: [4]Damien Cannane

   Explanation: Braided and serpentine filaments of glowing gas suggest
   this nebula's popular name, The Medusa Nebula. Also known as Abell 21,
   this Medusa is an old [5]planetary nebula some 1,500 light-years away
   in the constellation Gemini. Like its [6]mythological namesake, the
   nebula is associated with a dramatic transformation. The [7]planetary
   nebula phase represents a final stage in [8]the evolution of low mass
   stars like the sun as they transform themselves from [9]red giants to
   hot white dwarf stars and in the process shrug off their outer layers.
   Ultraviolet [10]radiation from the hot star powers the nebular glow.
   The Medusa's transforming star is the faint one near the center of the
   overall bright crescent shape. In [11]this deep telescopic view,
   fainter filaments clearly extend above and left of the bright crescent
   region. The Medusa Nebula is estimated to be over [12]4 light-years
   across.

                      Tomorrow's picture: behind pluto
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    Authors & editors: [24]Robert Nemiroff ([25]MTU) & [26]Jerry Bonnell
                                 ([27]UMCP)
          NASA Official: Phillip Newman [28]Specific rights apply.
              [29]NASA Web Privacy Policy and Important Notices
                A service of: [30]ASD at [31]NASA / [32]GSFC
                           & [33]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2203/Medusa_Nebula_141_x_180s.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://www.astrobin.com/users/Damien.Cannane/
   5. https://www.messier.seds.org/planetar.html
   6. http://en.wikipedia.org/wiki/Medusa
   7. https://en.wikipedia.org/wiki/Planetary_nebula
   8. http://casswww.ucsd.edu/public/tutorial/StevI.html
   9. http://en.wikipedia.org/wiki/Red_giant
  10. http://hyperphysics.phy-astr.gsu.edu/hbase/ems1.html
  11. https://www.astrobin.com/xbzfd8/
  12. https://www.nasa.gov/content/discoveries-hubbles-nebulae
  13. https://apod.nasa.gov/apod/ap220324.html
  14. https://apod.nasa.gov/apod/archivepix.html
  15. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  16. https://apod.nasa.gov/apod/lib/aptree.html
  17. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  18. https://apod.nasa.gov/apod/calendar/allyears.html
  19. https://apod.nasa.gov/apod.rss
  20. https://apod.nasa.gov/apod/lib/edlinks.html
  21. https://apod.nasa.gov/apod/lib/about_apod.html
  22. http://asterisk.apod.com/discuss_apod.php?date=220325
  23. https://apod.nasa.gov/apod/ap220326.html
  24. http://www.phy.mtu.edu/faculty/Nemiroff.html
  25. http://www.phy.mtu.edu/
  26. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  27. http://www.astro.umd.edu/
  28. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  29. https://www.nasa.gov/about/highlights/HP_Privacy.html
  30. https://astrophysics.gsfc.nasa.gov/
  31. https://www.nasa.gov/
  32. https://www.nasa.gov/centers/goddard/
  33. http://www.mtu.edu/