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 April 2
     [2]A colorful oval nebula is shown star field is shown in a sparse
       starfield. Fainter red nebulosity surrounds the bright oval. A
     relatively bright star is seen in the oval's center. Please see the
                 explanation for more detailed information.

                      M57: The Ring Nebula from Hubble
    Image Credit: [3]NASA, [4]ESA, [5]Hubble Legacy Archive; Processing:
                               [6]Judy Schmidt

   Explanation: It was noticed hundreds of years ago by stargazers who
   [7]could not understand its unusual shape. It looked like a ring on the
   sky. Except for the rings [8]of Saturn, the [9]Ring Nebula (M57) may be
   the most famous celestial circle. We now know what it is, and that its
   [10]iconic shape is due to our lucky perspective. The recent mapping of
   the [11]expanding nebula's [12]3-D structure, based in part on [13]this
   clear Hubble image,indicates that the nebula is a relatively dense,
   donut-like ring wrapped around the middle of an (American)
   [14]football-shaped cloud of glowing gas. Our view from [15]planet
   Earth looks down the long axis of the football, face-on to the ring. Of
   course, in this well-studied example of a [16]planetary nebula, the
   glowing material [17]does not come from planets. Instead, the gaseous
   shroud represents outer layers expelled from the dying, [18]once
   sun-like star, now a tiny pinprick of light seen at the nebula's
   center. Intense [19]ultraviolet light from the hot central star
   [20]ionizes atoms in the gas. The [21]Ring Nebula is about one
   [22]light-year across and 2,500 light-years away.

       Tomorrow's picture: [23]the beasts at the center of our galaxy
     __________________________________________________________________

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    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]NASA Science Activation
                           & [45]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2304/Ring_HubbleSchmidt_1548.jpg
   3. https://www.nasa.gov/
   4. https://www.esa.int/
   5. https://hla.stsci.edu/
   6. https://geckzilla.com/
   7. https://www.intermountainpet.com/hs-fs/hubfs/Blog_Images/Dogs-tilting-their-heads.jpg?width=900&name=Dogs-tilting-their-heads.jpg
   8. https://solarsystem.nasa.gov/planets/saturn/overview/
   9. https://en.wikipedia.org/wiki/Ring_Nebula
  10. https://apod.nasa.gov/apod/ap120915.html
  11. https://ui.adsabs.harvard.edu/abs/2013AJ....145..170O/abstract
  12. https://svs.gsfc.nasa.gov/31045
  13. https://www.flickr.com/photos/geckzilla/10055992403/
  14. https://en.wikipedia.org/wiki/Ball_(gridiron_football)
  15. https://solarsystem.nasa.gov/planets/earth/in-depth/
  16. https://apod.nasa.gov/apod/ap110218.html
  17. https://apod.nasa.gov/apod/ap110901.html
  18. https://en.wikipedia.org/wiki/Planetary_nebula
  19. https://science.nasa.gov/ems/10_ultravioletwaves
  20. https://hyperphysics.phy-astr.gsu.edu/hbase/mod4.html#c3
  21. https://apod.nasa.gov/apod/ap210818.html
  22. https://spaceplace.nasa.gov/light-year/en/
  23. https://apod.nasa.gov/apod/ap230403.html
  24. https://apod.nasa.gov/apod/ap230401.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. https://asterisk.apod.com/discuss_apod.php?date=230402
  34. https://apod.nasa.gov/apod/ap230403.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. https://science.nasa.gov/learners
  45. http://www.mtu.edu/