                        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.

                              2021 September 12

                        A Spiral Aurora over Iceland
                   Image Credit & Copyright: Davide Necchi

   Explanation: What's happened to the sky? Aurora! Captured in 2015, this
   aurora was noted by Icelanders for its great brightness and quick
   development. The aurora resulted from a solar storm, with high energy
   particles bursting out from the Sun and through a crack in Earth's
   protective magnetosphere a few days later. Although a spiral pattern
   can be discerned, creative humans might imagine the complex glow as an
   atmospheric apparition of any number of common icons. In the foreground
   of the featured image is the Ölfusá River while the lights illuminate a
   bridge in Selfoss City. Just beyond the low clouds is a nearly full
   Moon. The liveliness of the Sun -- and likely the resulting auroras on
   Earth -- is slowly increasing as the Sun emerges from a Solar minimum,
   a historically quiet period in its 11-year cycle.

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