      APOD: 2017 August 8 - Density Waves in Saturns Rings from Cassini

                         Astronomy Picture of the Day

    Discover the cosmos! [1] Each day a different image or photograph of our
 fascinating universe is featured, along with a brief explanation written by a
                           professional astronomer.

                                2017 August 8
                                      [2]
                 Density Waves in Saturn's Rings from Cassini
 Image Credit & License [3] : NASA [4] / JPL [5] / SSI [6] ; Digital Composite
                : Emily Lakdawalla [7] (Planetary Society [8] )

Explanation: What causes the patterns in Saturn's rings? The Cassini
spacecraft [9] , soon ending its 13 years orbiting Saturn [10] , has sent back
another spectacular image [11]  of Saturn's immense ring system [12]  in
unprecedented [13]  detail [14] . The physical cause for some of Saturn's ring
structures [15]  is not always understood. The cause for the beautifully
geometric type of ring structure shown here [16]  in ring of Saturn [17] ,
however, is surely a density wave [18] . A small moon systematically
perturbing the orbits of ring particles [19] circling Saturn at slightly
different distances causes such a density wave [20]  bunching. Also visible on
the lower right of the image [21]  is a bending wave [22] , a vertical wave in
ring particles also caused by the gravity of a nearby moon. Cassini's final
orbits [23]  are allowing a series of novel scientific measurements [24] and
images of the Solar System's most grand ring system [25] .

Open Science: Browse 1,500+ codes in the Astrophysics Source Code Library [26]

                      Tomorrow's picture: open space [27]

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Site notes:
  [1] archivepix.html
  [2] image/1708/RingWaves_CassiniLakdawalla_1020.jpg
  [3] https://creativecommons.org/licenses/by-nc-sa/3.0/
  [4] https://www.nasa.gov/
  [5] https://www.jpl.nasa.gov/
  [6] http://ciclops.org
  [7] http://www.planetary.org/about/staff/emily-lakdawalla.html
  [8] http://www.planetary.org/
  [9] https://saturn.jpl.nasa.gov/the-journey/the-spacecraft/
  [10] https://solarsystem.nasa.gov/planets/Saturn
  [11] https://apod.nasa.gov/cgi-bin/apod/apod_search?tquery=Cassini
  [12] https://saturn.jpl.nasa.gov/science/rings/
  [13] https://www.jpl.nasa.gov/news/news.php?feature=6729
  [14] ap040702.html
  [15] ap090602.html
  [16]
http://www.planetary.org/multimedia/space-images/saturn/
fine-scale-waves-in-saturns.html
  [17] https://en.wikipedia.org/wiki/Rings_of_Saturn
  [18] http://adsabs.harvard.edu/abs/1978Icar...34..240G
  [19] ap050525.html
  [20] https://www.youtube.com/watch?v=Xtw4cEjFBDs
  [21]
http://www.planetary.org/multimedia/space-images/saturn/
fine-scale-waves-in-saturns.html
  [22] https://saturn.jpl.nasa.gov/resources/4291/
  [23] ap170125.html
  [24]
http://www.planetary.org/blogs/emily-lakdawalla/2017/
0703-cassini-end-preview-preview.html
  [25] ap071023.html
  [26] http://ascl.net/code/all
  [27] ap170809.html
  [28] ap170807.html
  [29] archivepix.html
  [30] lib/apsubmit2015.html
  [31] lib/aptree.html
  [32] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [33] calendar/allyears.html
  [34] /apod.rss
  [35] lib/edlinks.html
  [36] lib/about_apod.html
  [37] http://asterisk.apod.com/discuss_apod.php?date=170808
  [38] ap170809.html
  [39] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [40] http://www.phy.mtu.edu/
  [41] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
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