                        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 March 12
   An oblong moon is shown that appears sponge like and features many odd
    craters. Close inspection shows that the bottoms of these craters are
      covered with a dark material. Please see the explanation for more
                            detailed information.

                 Saturn's Hyperion: A Moon with Odd Craters
           Image Credit: NASA, ESA, JPL, SSI, Cassini Imaging Team

   Explanation: What lies at the bottom of Hyperion's strange craters? To
   help find out, the robot Cassini spacecraft that once orbited Saturn
   swooped past the sponge-textured moon and took images of unprecedented
   detail. A six-image mosaic from the 2005 pass, featured here in
   scientifically assigned colors, shows a remarkable world strewn with
   strange craters and an odd, sponge-like surface. At the bottom of most
   craters lies some type of unknown dark reddish material. This material
   appears similar to that covering part of another of Saturn's moons,
   Iapetus, and might sink into the ice moon as it better absorbs warming
   sunlight. Hyperion is about 250 kilometers across, rotates chaotically,
   and has a density so low that it likely houses a vast system of caverns
   inside.

                       Tomorrow's picture: tree colors
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                           NASA Science Activation
                             & Michigan Tech. U.

