                        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 August 27
   A night view of a waterfall with a colorful aurora in shades of green,
            yellow, red and purple, and stars in the background.

                  Colorful Aurora over Icelandic Waterfall
                    Image Credit & Copyright: Victor Lima
             Text: Cecilia Chirenti (NASA GSFC, UMCP, CRESST II)

   Explanation: What a sight to behold, when a night sky became filled
   with colors that appeared to rain over the Skógafoss waterfall in
   Iceland. This image was taken in a single 5 second exposure by the
   photographer in April 2025. Seeing an aurora is on many people's bucket
   lists. But it is not easy. It requires high solar activity, dark and
   clear skies, and usually a viewing location at high latitude. That
   makes the northern lights more easily seen than the corresponding
   southern lights, simply because there is less landmass in the Southern
   Hemisphere, especially around the Antarctic Circle. Auroras are caused
   by charged particles from the solar wind that are captured by the
   Earth's magnetosphere and guided by the magnetic field to a region
   close to one of the poles, where they collide with gas particles in the
   atmosphere. Different colors indicate interactions with different gases
   at different altitudes, like oxygen (red and green) and nitrogen (blue
   and pink).

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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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