                        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 October 23
    Jupiter's moon Io is shown as photogaphred recently by NASA's passing
    Juno spacecraft. The moon is nearly half- lit by the distant Sun and
    shows a complex surface including the colors yellow, orange, and dark
   brown. Near the top, the plume of an active volcano can be seen. Please
             see the explanation for more detailed information.

                        Moon Io from Spacecraft Juno
    Image Credit: NASA, JPL-Caltech, SwRI, MSSS; Processing & Copyright:
                     Ted Stryk & Fernando García Navarro

   Explanation: There goes another one! Volcanoes on Jupiter's moon Io
   keep erupting. To investigate, NASA's robotic Juno spacecraft has begun
   a series of visits to this very strange moon. Io is about the size of
   Earth's moon, but because of gravitational flexing by Jupiter and other
   moons, Io's interior gets heated and its surface has become covered
   with volcanoes. The featured image is from last week's flyby, passing
   within 12,000 kilometers above the dangerously active world. The
   surface of Io is covered with sulfur and frozen sulfur dioxide, making
   it appear yellow, orange and brown. As hoped, Juno flew by just as a
   volcano was erupting -- with its faint plume visible near the top of
   the featured image. Studying Io's volcanoes and plumes helps humanity
   better understand how Jupiter's complex system of moons, rings, and
   auroras interact. Juno is scheduled to make two flybys of Io during the
   coming months that are almost 10 times closer: one in December and
   another in February 2024.

   Help Wanted: Professional-astronomer level guest writers and assistant
                              editors for APOD
                       Tomorrow's picture: eclipse sky
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                             & Michigan Tech. U.

