                        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 July 30
   A bright green spiral aurora is seen in a break in the clouds before a
      purple background. The foreground contains green grassland and a
         circular lake. Please see the explanation for more detailed
                                information.

                     Spiral Aurora over Icelandic Divide
      Image Credit & Copyright: Juan Carlos Casado (Starry Earth, TWAN)

   Explanation: Admire the beauty but fear the beast. The beauty is the
   aurora overhead, here taking the form of a great green spiral, seen
   between picturesque clouds with the bright Moon to the side and stars
   in the background. The beast is the wave of charged particles that
   creates the aurora but might, one day, impair civilization. In 1859,
   following notable auroras seen all across the globe, a pulse of charged
   particles from a coronal mass ejection (CME) associated with a solar
   flare impacted Earth's magnetosphere so forcefully that it created the
   Carrington Event. This assault from the Sun compressed the Earth's
   magnetic field so violently that it created high currents and sparks
   along telegraph wires, shocking many telegraph operators. Were a
   Carrington-class event to impact the Earth today, speculation holds
   that damage might occur to global power grids and electronics on a
   scale never yet experienced. The featured aurora was imaged in 2016
   over Thingvallavatn Lake in Iceland, a lake that partly fills a fault
   that divides Earth's large Eurasian and North American tectonic plates.

                  Almost Hyperspace: Random APOD Generator
                     Tomorrow's picture: moon over mars
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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