Astronomy Picture of the Day

   [1]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
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                             The Umbra of Earth
       Image Credit & [3]Copyright: [4]Wang Letian ([5]Eyes at Night)

   Explanation: The dark, inner shadow of planet Earth is called [6]the
   umbra. Shaped like a cone extending into space, it has a circular cross
   section most easily seen during a [7]lunar eclipse. And on the night of
   September 7/8 the [8]Full Moon passed near the center of Earth's umbral
   cone, [9]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 [10]the total lunar eclipse, progressing
   left to right, to reveal the curved cross-section of the [11]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. [12]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 [13]leisurely lunar eclipse, the Moon was
   completely within the Earth's umbra for about 83 minutes.

                Tomorrow's picture: a tale of two hemispheres
     __________________________________________________________________

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    Authors & editors: [25]Robert Nemiroff ([26]MTU) & [27]Jerry Bonnell
                                 ([28]UMCP)
          NASA Official: Amber Straughn [29]Specific rights apply.
            [30]NASA Web Privacy, [31]Accessibility, [32]Notices;
                A service of: [33]ASD at [34]NASA / [35]GSFC,
                         [36]NASA Science Activation
                           & [37]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2509/UmbraEarth.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. http://www.luckwlt.com/About Me.html
   5. http://www.luckwlt.com/
   6. https://apod.nasa.gov/apod/ap060909.html
   7. https://solarsystem.nasa.gov/moons/earths-moon/lunar-eclipses/
   8. https://earthsky.org/astronomy-essentials/total-lunar-eclipse-september-7-2025/
   9. https://apod.nasa.gov/apod/ap190125.html
  10. https://science.nasa.gov/moon/eclipses/
  11. https://apod.nasa.gov/apod/ap080820.html
  12. https://apod.nasa.gov/apod/ap151003.html
  13. https://en.wikipedia.org/wiki/Lunar_eclipse#Total_lunar_eclipse
  14. https://apod.nasa.gov/apod/ap250910.html
  15. https://apod.nasa.gov/apod/archivepix.html
  16. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  17. https://apod.nasa.gov/apod/lib/aptree.html
  18. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  19. https://apod.nasa.gov/apod/calendar/allyears.html
  20. https://apod.com/feed.rss
  21. https://apod.nasa.gov/apod/lib/edlinks.html
  22. https://apod.nasa.gov/apod/lib/about_apod.html
  23. https://asterisk.apod.com/discuss_apod.php?date=250911
  24. https://apod.nasa.gov/apod/ap250912.html
  25. http://www.phy.mtu.edu/faculty/Nemiroff.html
  26. http://www.phy.mtu.edu/
  27. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  28. http://www.astro.umd.edu/
  29. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  30. https://www.nasa.gov/about/highlights/HP_Privacy.html
  31. https://www.nasa.gov/general/accessibility/
  32. https://www.nasa.gov/privacy/
  33. https://astrophysics.gsfc.nasa.gov/
  34. https://www.nasa.gov/
  35. https://www.nasa.gov/centers/goddard/
  36. https://science.nasa.gov/learners
  37. http://www.mtu.edu/