                        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.

                                 2026 June 6

                            Charon: Moon of Pluto
       Image Credit: NASA, Johns Hopkins Univ./APL, Southwest Research
                      Institute, U.S. Naval Observatory

   Explanation: A darkened and mysterious north polar region known to some
   as Mordor Macula caps this premier view of Charon, Pluto's largest
   moon. The high-resolution image was captured by the interplanetary
   space probe New Horizons near its closest approach to distant Pluto on
   July 14, 2015. The combined blue, red, and infrared image data was
   processed to enhance colors and follow variations in Charon's surface
   properties with a resolution of about 2.9 kilometers (1.8 miles). A
   stunning image of Charon's Pluto-facing hemisphere, it also features a
   clear view of an apparently moon-girdling belt of fractures and canyons
   that seems to separate smooth southern plains from varied northern
   terrain. Charon is 1,214 kilometers (754 miles) across. That's about
   1/10th the size of planet Earth but a whopping 1/2 the diameter of
   Pluto itself, and makes it the largest satellite relative to its parent
   body in the Solar System. Still, the moon appears as a small bump at
   about the 1 o'clock position on Pluto's disk in the grainy, negative,
   telescopic picture inset at upper left. That image was used by James
   Christy and Robert Harrington at the U.S. Naval Observatory in
   Flagstaff to discover Charon in June of 1978.

              Tomorrow's picture: Jupiter and Venus from Earth
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                           NASA Science Activation
                             & Michigan Tech. U.

