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.

                                2025 April 29
   [2]The planet Saturn is shown many times down the composite image. The
     top image was taken in 2020 and shows Saturn's rings very clearly,
      whereas the bottom image was taken in 2025 and the rings are only
      visible as a dark line across the planet. The six images show the
   progression year by year. Please see the explanation for more detailed
                                information.

                     Saturn's Rings Appear to Disappear
                  Image Credit & Copyright: [3]Natan Fontes

   Explanation: Where are Saturn's ears? [4]Galileo is credited, in 1610,
   as the first person to see [5]Saturn's rings. Testing out
   [6]Lipperhey's recently [7]co-invented telescope, Galileo did not know
   what they were and so called them "[8]ears". The mystery deepened in
   1612, when Saturn's ears [9]mysteriously disappeared. Today we know
   exactly what happened: from the perspective of the [10]Earth, Saturn's
   rings had become [11]too thin to see. The same drama [12]plays out
   every 15 years because Saturn, like Earth, undergoes [13]tilt-driven
   seasons. This means that as Saturn goes around the Sun, its [14]equator
   and [15]rings can tilt noticeably toward the Sun and inner [16]Solar
   System, making them easily visible, but from other orbital locations
   will appear almost not at all. The [17]featured picture from
   [18]Brasilia, [19]Brazil shows a modern version of this sequence: the
   top ring-dominated image was taken in 2020, while the bottom
   ring-obscure image taken earlier in 2025.

           Make Saturn's Rings Musical: [20]Play them like a harp!
                       Tomorrow's picture: smiling sky
     __________________________________________________________________

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    Authors & editors: [32]Robert Nemiroff ([33]MTU) & [34]Jerry Bonnell
                                 ([35]UMCP)
          NASA Official: Amber Straughn [36]Specific rights apply.
            [37]NASA Web Privacy, [38]Accessibility, [39]Notices;
                A service of: [40]ASD at [41]NASA / [42]GSFC,
                         [43]NASA Science Activation
                           & [44]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2504/SaturnSeasons_Fontes_960.jpg
   3. https://telescopius.com/profile/natan_fontes
   4. https://en.wikipedia.org/wiki/Galileo_Galilei
   5. https://science.nasa.gov/resource/saturns-rings-2/
   6. https://en.wikipedia.org/wiki/Hans_Lipperhey
   7. https://en.wikipedia.org/wiki/History_of_the_telescope
   8. https://en.wikipedia.org/wiki/Rings_of_Saturn#History
   9. https://www.petsonme.com.au/blog/wp-content/uploads/2022/01/Why-Do-Dogs-tilt-their-head-scaled.jpeg
  10. https://earthobservatory.nasa.gov/
  11. https://apod.nasa.gov/apod/ap100215.html
  12. https://apod.nasa.gov/apod/ap150621.html
  13. https://spaceplace.nasa.gov/seasons/en/
  14. https://www.nasa.gov/wp-content/uploads/2015/06/equator_.png
  15. https://apod.nasa.gov/apod/ap180424.html
  16. https://eyes.nasa.gov/apps/solar-system/#/home
  17. https://telescopius.com/pictures/view/224831/planet/by-natan_fontes
  18. https://youtu.be/m8fZeZTN0TE
  19. https://en.wikipedia.org/wiki/Brazil
  20. https://apod.nasa.gov/apod/ap180424.html
  21. https://apod.nasa.gov/apod/ap250428.html
  22. https://apod.nasa.gov/apod/archivepix.html
  23. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  24. https://apod.nasa.gov/apod/lib/aptree.html
  25. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  26. https://apod.nasa.gov/apod/calendar/allyears.html
  27. https://apod.com/feed.rss
  28. https://apod.nasa.gov/apod/lib/edlinks.html
  29. https://apod.nasa.gov/apod/lib/about_apod.html
  30. https://asterisk.apod.com/discuss_apod.php?date=250429
  31. https://apod.nasa.gov/apod/ap250430.html
  32. http://www.phy.mtu.edu/faculty/Nemiroff.html
  33. http://www.phy.mtu.edu/
  34. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  35. http://www.astro.umd.edu/
  36. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  37. https://www.nasa.gov/about/highlights/HP_Privacy.html
  38. https://www.nasa.gov/general/accessibility/
  39. https://www.nasa.gov/privacy/
  40. https://astrophysics.gsfc.nasa.gov/
  41. https://www.nasa.gov/
  42. https://www.nasa.gov/centers/goddard/
  43. https://science.nasa.gov/learners
  44. http://www.mtu.edu/