                        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 February 9

                        Nacreous Clouds over Lapland
                  Image Credit & Copyright: Dennis Lehtonen

   Explanation: Vivid and lustrous, wafting iridescent waves of color wash
   across this skyscape from Kilpisjärvi, Finland. Known as nacreous
   clouds or mother-of-pearl clouds, they are rare. But their
   unforgettable appearance was captured looking south at 69 degrees north
   latitude at sunset on January 24. A type of polar stratospheric cloud,
   they form when unusually cold temperatures in the usually cloudless
   lower stratosphere form ice crystals. Still sunlit at altitudes of
   around 15 to 25 kilometers, the clouds can diffract sunlight even after
   sunset and just before the dawn.

                     Tomorrow's picture: pixels in space
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