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.

                               2019 October 8

                           Sprite Lightning in HD
              Image Credit & Copyright: Stephane Vetter (TWAN)

   Explanation: This phenomenon occurs in the sky over our heads, not the
   sea. It is a type of lightning known as red sprite, and rarely has it
   ever been photographed in this detail. Even though sprites have been
   recorded for over 30 years, their root cause remains unknown. Some
   thunderstorms have them, but most don't. These mysterious bursts of
   light in the upper atmosphere momentarily resemble gigantic jellyfish.
   A few years ago high speed videos were taken detailing how red sprites
   actually develop. The featured image was captured last month in high
   definition from Italy. One unusual feature of sprites is that they are
   relatively cold -- they operate more like long fluorescent light tubes
   than hot compact light bulbs. In general, red sprites take only a
   fraction of a second to occur and are best seen when powerful
   thunderstorms are visible from the side.

                        Tomorrow's picture: starburst
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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.

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