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 July 26

                                            The Veins of Heaven
                          Image Credit & Copyright: P-M Hedén (Clear
Skies, TWAN)

   Explanation: Transfusing sunlight through a still dark sky, this
exceptional display of noctilucent
   clouds was captured earlier this month, reflected in the calm waters of
Vallentuna Lake near
   Stockholm, Sweden. From the edge of space, about 80 kilometers above
Earth's surface, the icy clouds
   themselves still reflect sunlight even though the Sun is below the
horizon as seen from the ground.
   Usually spotted at high latitudes in summer months the night shining
clouds have made a strong showing
   so far during the short northern summer nights. Also known as polar
mesopheric clouds they are
   understood to form as water vapor driven into the cold upper atmosphere
condenses on the fine dust
   particles supplied by disintegrating meteors or volcanic ash. NASA's AIM
mission provides daily
   projections of noctilucent clouds as seen from space.

                                 Tomorrow's picture: launch and last light
    
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                      Authors & editors: Robert Nemiroff (MTU) &
Jerry Bonnell (UMCP)
                            NASA Official: Phillip Newman Specific rights apply.
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