                APOD: 2017 August 29 - Saturn in Blue and Gold

                         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 29
                                      [2]
                           Saturn in Blue and Gold
  Image Credit: Cassini Imaging Team [3] , SSI [4] , JPL [5] , ESA [6] , NASA
                                      [7]

Explanation: Why is Saturn partly blue? The featured picture [8] of Saturn
approximates what a human [9] would see if hovering close to the giant ringed
world. The image [10] was taken in 2006 March by the robot Cassini spacecraft
[11]  now orbiting Saturn [12] . Here Saturn's majestic rings [13]  appear
directly only as a thin vertical line. The rings show their complex structure
in the dark shadows they create on the image left. Saturn's fountain moon
Enceladus [14] , only about 500 kilometers across, is seen as the bump in the
plane of the rings. The northern hemisphere of Saturn can appear partly blue
[15]  for the same reason that Earth's skies can appear blue [16]  --
molecules in the cloudless portions of both planet's atmospheres are better at
scattering blue light than red. When looking deep into Saturn's clouds [17] ,
however, the natural gold hue of Saturn's clouds becomes dominant. It is not
known [18]  why southern Saturn does not show the same blue hue -- one
hypothesis holds that clouds are higher there. It is also not known [19]  why
Saturn's clouds are colored [20]  gold. Next month, Cassini will end its
mission [21]  with a final dramatic dive [22]  into Saturn's atmosphere.

    Eclipses 2017: Memorable images submitted to APOD -- please "Like" your
                               favorites. [23]
                  Tomorrow's picture: princely eclipse [24]

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    Authors & editors: Robert Nemiroff [36] (MTU [37] ) & Jerry Bonnell [38]
                                  (UMCP [39] )
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Site notes:
  [1] archivepix.html
  [2] image/1708/saturnbluegold_cassini_1016.jpg
  [3] http://ciclops.org/
  [4] http://www.spacescience.org/
  [5] http://www.jpl.nasa.gov/
  [6] http://www.esa.int/
  [7] https://www.nasa.gov/
  [8] http://photojournal.jpl.nasa.gov/catalog/PIA08166
  [9] ap160815.html
  [10] http://photojournal.jpl.nasa.gov/catalog/PIA08166
  [11] http://www.esa.int/esaMI/Cassini-Huygens/SEM9D2HHZTD_0.html
  [12] https://solarsystem.nasa.gov/planets/Saturn
  [13] http://en.wikipedia.org/wiki/Saturn%27s_rings
  [14] ap060310.html
  [15] https://www.nasa.gov/mission_pages/cassini/multimedia/pia06177.html
  [16] http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html
  [17] ap051010.html
  [18] http://honesttopaws.com/wp-content/uploads/2015/11/head-tilt.jpg
  [19] http://adsabs.harvard.edu/abs/2004cosp...35..466W
  [20] ap960803.html
  [21] ap170125.html
  [22]
http://www.planetary.org/blogs/emily-lakdawalla/2017/
0703-cassini-end-preview-preview.html
  [23]
https://www.facebook.com/pg/AstronomyPictureOfTheDay/photos/
?tab=album&album_id=1396657207036403
  [24] ap170830.html
  [25] ap170828.html
  [26] archivepix.html
  [27] lib/apsubmit2015.html
  [28] lib/aptree.html
  [29] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [30] calendar/allyears.html
  [31] /apod.rss
  [32] lib/edlinks.html
  [33] lib/about_apod.html
  [34] http://asterisk.apod.com/discuss_apod.php?date=170829
  [35] ap170830.html
  [36] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [37] http://www.phy.mtu.edu/
  [38] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  [39] http://www.astro.umd.edu/
  [40] lib/about_apod.html#srapply
  [41] https://www.nasa.gov/about/highlights/HP_Privacy.html
  [42] https://astrophysics.gsfc.nasa.gov/
  [43] https://www.nasa.gov/
  [44] https://www.nasa.gov/centers/goddard/
  [45] http://www.mtu.edu/
