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 August 17
    [2]The picture shows M57, the Ring Nebula, as captured by the Hubble
        Space Telescope. 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: Except for the rings [7]of Saturn, the [8]Ring Nebula
   (M57) is probably the most famous celestial circle. Its classic
   appearance is [9]understood to be due to our own perspective, though.
   The recent mapping of the [10]expanding nebula's [11]3-D structure,
   based in part on [12]this clear Hubble image,indicates that the nebula
   is a relatively dense, donut-like ring wrapped around the middle of a
   (American) [13]football-shaped cloud of glowing gas. The view from
   [14]planet Earth looks down the long axis of the football, face-on to
   the ring. Of course, in this well-studied example of a [15]planetary
   nebula, the glowing material [16]does not come from planets. Instead,
   the gaseous shroud represents outer layers expelled from the dying,
   [17]once sun-like star, now a tiny pinprick of light seen at the
   nebula's center. Intense [18]ultraviolet light from the hot central
   star [19]ionizes atoms in the gas. The [20]Ring Nebula is about one
   [21]light-year across and 2,500 light-years away.

   Share the Sky: [22]NASA Open API [23]for APOD Tomorrow's picture: rings
                                  upon Ring
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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]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2108/Ring_HubbleSchmidt_1548.jpg
   3. https://www.nasa.gov/
   4. https://www.esa.int/
   5. http://hla.stsci.edu/
   6. https://geckzilla.com/
   7. https://solarsystem.nasa.gov/planets/saturn/overview/
   8. http://messier.seds.org/m/m057.html
   9. https://cdn.pixabay.com/photo/2019/09/04/08/24/cat-4451003_960_720.jpg
  10. https://ui.adsabs.harvard.edu/abs/2013AJ....145..170O/abstract
  11. https://svs.gsfc.nasa.gov/31045
  12. https://www.flickr.com/photos/geckzilla/10055992403/
  13. https://en.wikipedia.org/wiki/Ball_(gridiron_football)
  14. https://solarsystem.nasa.gov/planets/earth/in-depth/
  15. https://apod.nasa.gov/apod/ap110218.html
  16. https://apod.nasa.gov/apod/ap110901.html
  17. https://en.wikipedia.org/wiki/Planetary_nebula
  18. https://science.nasa.gov/ems/10_ultravioletwaves
  19. http://hyperphysics.phy-astr.gsu.edu/hbase/mod4.html#c3
  20. https://apod.nasa.gov/apod/ap140813.html
  21. https://spaceplace.nasa.gov/light-year/en/
  22. https://api.nasa.gov/
  23. https://github.com/nasa/apod-api
  24. https://apod.nasa.gov/apod/ap210816.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=210817
  34. https://apod.nasa.gov/apod/ap210818.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/