                        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.

                               2024 January 25

                            Jyväskylä in the Sky
                  Image Credit & Copyright: Harri Kiiskinen

   Explanation: You might not immediately recognize this street map of a
   neighborhood in Jyväskylä, Finland, planet Earth. But that's probably
   because the map was projected into the night sky and captured with an
   allsky camera on January 16. The temperature recorded on that northern
   winter night was around minus 20 degrees Celsius. As ice crystals
   formed in the atmosphere overhead, street lights spilling illumination
   into the sky above produced visible light pillars, their ethereal
   appearance due to specular reflections from the fluttering crystals'
   flat surfaces. Of course, the projected light pillars trace a map of
   the brightly lit local streets, though reversed right to left in the
   upward looking camera's view. This light pillar street map was seen to
   hover for hours in the Jyväskylä night.

                    Tomorrow's picture: star with planet
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

