                        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 November 11

                          The SAR and the Milky Way
                   Image Credit & Copyright: Julien Looten

   Explanation: This broad, luminous red arc was a surprising visitor to
   partly cloudy evening skies over northern France. Captured extending
   toward the zenith in a west-to-east mosaic of images from November 5,
   the faint atmospheric ribbon of light is an example of a Stable Auroral
   Red (SAR) arc. The rare night sky phenomenon was also spotted at
   unusually low latitudes around world, along with more dynamic auroral
   displays during an intense geomagnetic storm. SAR arcs and their
   relation to auroral emission have been explored by citizen science and
   satellite investigations. From altitudes substantially above the normal
   auroral glow, the deep red SAR emission is thought to be caused by
   strong heating due to currents flowing in planet Earth's inner
   magnetosphere. Beyond this SAR, the Milky Way arcs above the cloud
   banks along the horizon, a regular visitor to night skies over northern
   France.

                        Tomorrow's picture: snow day
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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