                        Astronomy Picture of the Day

    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 30
    An oblong moon is shown in very muted colors, appearing almost gray.
   The background is deep space and completely dark at this short exposure
       time. Please see the explanation for more detailed information.

                        Saturn's Moon Helene in Color
      Image Credit: NASA, JPL-Caltech, SSI; Processing: Daniel Macháček

   Explanation: Although its colors may be subtle, Saturn's moon Helene is
   an enigma in any light. The moon was imaged in unprecedented detail in
   2012 as the robotic Cassini spacecraft orbiting Saturn swooped to
   within a single Earth diameter of the diminutive moon. Although
   conventional craters and hills appear, the above image also shows
   terrain that appears unusually smooth and streaked. Planetary
   astronomers are inspecting these detailed images of Helene to glean
   clues about the origin and evolution of the 30-km across floating
   iceberg. Helene is also unusual because it circles Saturn just ahead of
   the large moon Dione, making it one of only four known Saturnian moons
   to occupy a gravitational well known as a stable Lagrange point.

                    Tomorrow's picture: stars with colors
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

