                        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.

                              2025 September 11

                             The Umbra of Earth
            Image Credit & Copyright: Wang Letian (Eyes at Night)

   Explanation: The dark, inner shadow of planet Earth is called the
   umbra. Shaped like a cone extending into space, it has a circular cross
   section most easily seen during a lunar eclipse. And on the night of
   September 7/8 the Full Moon passed near the center of Earth's umbral
   cone, entertaining eclipse watchers around much of our fair planet,
   including parts of Antarctica, Australia, Asia, Europe, and Africa.
   Recorded from Zhangjiakou City, China, this timelapse composite image
   uses successive pictures from the total lunar eclipse, progressing left
   to right, to reveal the curved cross-section of the umbral shadow
   sliding across the Moon. Sunlight scattered by the atmosphere into
   Earth's umbra causes the lunar surface to appear reddened during
   totality. But close to the umbra's edge, the limb of the eclipsed Moon
   shows a distinct blue hue. The blue eclipsed moonlight originates as
   rays of sunlight pass through layers high in the upper stratosphere,
   colored by ozone that scatters red light and transmits blue. In the
   total phase of this leisurely lunar eclipse, the Moon was completely
   within the Earth's umbra for about 83 minutes.

                Tomorrow's picture: a tale of two hemispheres
     __________________________________________________________________

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

