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.

                                2022 April 22
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                          Planet Earth at Twilight
       Image Credit: [3]ISS Expedition 2 Crew, [4]Gateway to Astronaut
                        Photography of Earth, [5]NASA

   Explanation: No sudden, sharp boundary marks the passage of day into
   night in [6]this gorgeous view of ocean and clouds over [7]our fair
   planet Earth. Instead, the shadow line or terminator is diffuse and
   shows the gradual transition to darkness we experience as twilight.
   With the Sun illuminating the scene from the right, the cloud tops
   reflect gently reddened [8]sunlight filtered through the dusty
   troposphere, the lowest layer of the planet's nurturing atmosphere. A
   clear high altitude layer, visible along the dayside's upper edge,
   [9]scatters blue sunlight and fades into the blackness of space. This
   picture was taken in June of 2001 from the International Space Station
   orbiting at an altitude of 211 nautical miles. Of course from home,
   [10]you can check out the Earth Now.

                      Celebrate: [11]Today is Earth Day
                       Tomorrow's picture: Messier 104
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      [12]< | [13]Archive | [14]Submissions | [15]Index | [16]Search |
   [17]Calendar | [18]RSS | [19]Education | [20]About APOD | [21]Discuss |
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     __________________________________________________________________

    Authors & editors: [23]Robert Nemiroff ([24]MTU) & [25]Jerry Bonnell
                                 ([26]UMCP)
          NASA Official: Phillip Newman [27]Specific rights apply.
              [28]NASA Web Privacy Policy and Important Notices
                A service of: [29]ASD at [30]NASA / [31]GSFC
                           & [32]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2204/ISS002-E-7377_2048c.jpg
   3. https://www.nasa.gov/mission_pages/station/expeditions/expedition02/index.html
   4. https://eol.jsc.nasa.gov/
   5. https://www.nasa.gov/
   6. http://eol.jsc.nasa.gov/scripts/sseop/photo.pl?mission=ISS002&roll=E&frame=7377
   7. https://earthobservatory.nasa.gov/features/NationalParks
   8. http://www.webexhibits.org/causesofcolor/14B.html
   9. http://webexhibits.org/causesofcolor/14.html
  10. https://climate.nasa.gov/earth-now/#/
  11. https://nasa.6connex.com/event/NASAScience/NASA-at-Earth-Day/login
  12. https://apod.nasa.gov/apod/ap220421.html
  13. https://apod.nasa.gov/apod/archivepix.html
  14. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  15. https://apod.nasa.gov/apod/lib/aptree.html
  16. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  17. https://apod.nasa.gov/apod/calendar/allyears.html
  18. https://apod.nasa.gov/apod.rss
  19. https://apod.nasa.gov/apod/lib/edlinks.html
  20. https://apod.nasa.gov/apod/lib/about_apod.html
  21. http://asterisk.apod.com/discuss_apod.php?date=220422
  22. https://apod.nasa.gov/apod/ap220423.html
  23. http://www.phy.mtu.edu/faculty/Nemiroff.html
  24. http://www.phy.mtu.edu/
  25. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  26. http://www.astro.umd.edu/
  27. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  28. https://www.nasa.gov/about/highlights/HP_Privacy.html
  29. https://astrophysics.gsfc.nasa.gov/
  30. https://www.nasa.gov/
  31. https://www.nasa.gov/centers/goddard/
  32. http://www.mtu.edu/