Subj : Daily APOD Report
To   : All
From : Alan Ianson
Date : Sun Jun 29 2025 00:21:46

                        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.

                                2025 June 29
     Viewed from above, a landscape on Mars features many ridges of pink
   sand. Superposed on some of these ridges are thin brown stipes. Please
             see the explanation for more detailed information.

                         Dark Sand Cascades on Mars
             Image Credit: NASA, HiRISE, MRO, LPL (U. Arizona),

   Explanation: Are these trees growing on Mars? No. Groups of dark brown
   streaks have been photographed by the Mars Reconnaissance Orbiter on
   melting pinkish sand dunes covered with light frost. The featured image
   was taken in 2008 April near the North Pole of Mars. At that time, dark
   sand on the interior of Martian sand dunes became more and more visible
   as the spring Sun melted the lighter carbon dioxide ice. When occurring
   near the top of a dune, dark sand may cascade down the dune leaving
   dark surface streaks -- streaks that might appear at first to be trees
   standing in front of the lighter regions but cast no shadows. Objects
   about 25 centimeters across are resolved on this image spanning about
   one kilometer. Close ups of some parts of this image show billowing
   plumes indicating that the sand slides were occurring even while the
   image was being taken.

     Celestial Surprise: What picture did APOD feature on your birthday?
                                 (post 1995)
                      Tomorrow's picture: raining stars
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
                  NASA Web Privacy, Accessibility, Notices;
                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

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 * Origin: The Rusty MailBox - Penticton, BC Canada (1:153/757)

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