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.

                              2024 February 28
    [2]A rocky shoreline is shown with land on the right and water on the
       left. Above is a sky that shows unusually pixelated and colored
        vertical bands. Please see the explanation for more detailed
                                information.

                               Shades of Night
                Image Credit & Copyright: [3]Dario Giannobile

   Explanation: How does the sky turn dark at night? In stages, and with
   different characteristic colors rising from the horizon. The
   [4]featured image shows, left to right, increasingly late [5]twilight
   times after sunset in 20 different vertical bands. The picture was
   taken last month in [6]Syracuse, [7]Sicily, [8]Italy, in the direction
   [9]opposite the Sun. On the far left is the pre-sunset upper sky.
   Toward the right, prominent bands include the [10]Belt of Venus, the
   [11]Blue Band, the [12]Horizon Band, and the Red Band. As the dark
   shadow of the Earth rises, the colors in these bands are [13]caused
   [14]by direct sunlight reflecting from air and [15]aerosols in the
   [16]Earth's atmosphere, multiple reflections sometimes involving a
   [17]reddened sunset, and [18]refraction. In practice, these bands can
   be diffuse and hard to discern, and their colors can depend on
   [19]colors near the setting Sun. Finally, the Sun [20]completely sets
   and the sky becomes dark. [21]Don't despair -- the whole thing will
   happen in reverse when the [22]Sun rises again in the morning.

                     Tomorrow's picture: extra February
     __________________________________________________________________

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    Authors & editors: [34]Robert Nemiroff ([35]MTU) & [36]Jerry Bonnell
                                 ([37]UMCP)
          NASA Official: Amber Straughn; [38]Specific rights apply.
              [39]NASA Web Privacy Policy and Important Notices
                A service of: [40]ASD at [41]NASA / [42]GSFC,
                         [43]NASA Science Activation
                           & [44]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2402/TwilightShades_Giannobile_1600.jpg
   3. https://www.instagram.com/astro_dariogiannobile/
   4. https://www.facebook.com/photo/?fbid=10231968620107561
   5. https://apod.nasa.gov/apod/ap230506.html
   6. https://youtu.be/zopIdrtkbVE
   7. https://youtu.be/NnKs9NDzvVs
   8. https://en.wikipedia.org/wiki/Italy
   9. https://apod.nasa.gov/apod/ap190624.html
  10. https://apod.nasa.gov/apod/ap230626.html
  11. https://twanight.org/gallery/the-elusive-bands-of-anti-twilight/
  12. https://epod.usra.edu/blog/2023/01/anti-tiwilight-colors-and-belt-of-venus.html
  13. https://www.eso.org/sci/publications/messenger/archive/no.178-dec19/messenger-no178-51-56.pdf
  14. https://opg.optica.org/ao/fulltext.cfm?uri=ao-56-19-G156&id=367436
  15. https://en.wikipedia.org/wiki/Aerosol
  16. https://climate.nasa.gov/news/2919/earths-atmosphere-a-multi-layered-cake/
  17. https://apod.nasa.gov/apod/ap170120.html
  18. https://en.wikipedia.org/wiki/Refraction
  19. https://apod.nasa.gov/apod/ap061221.html
  20. https://www.weather.gov/lmk/twilight-types
  21. https://qph.cf2.quoracdn.net/main-qimg-ad89b5e5f33336dc569bfe095c1342df-lq
  22. https://apod.nasa.gov/apod/ap231019.html
  23. https://apod.nasa.gov/apod/ap240227.html
  24. https://apod.nasa.gov/apod/archivepix.html
  25. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  26. https://apod.nasa.gov/apod/lib/aptree.html
  27. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  28. https://apod.nasa.gov/apod/calendar/allyears.html
  29. https://apod.com/feed.rss
  30. https://apod.nasa.gov/apod/lib/edlinks.html
  31. https://apod.nasa.gov/apod/lib/about_apod.html
  32. https://asterisk.apod.com/discuss_apod.php?date=240228
  33. https://apod.nasa.gov/apod/ap240229.html
  34. http://www.phy.mtu.edu/faculty/Nemiroff.html
  35. http://www.phy.mtu.edu/
  36. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  37. http://www.astro.umd.edu/
  38. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  39. https://www.nasa.gov/about/highlights/HP_Privacy.html
  40. https://astrophysics.gsfc.nasa.gov/
  41. https://www.nasa.gov/
  42. https://www.nasa.gov/centers/goddard/
  43. https://science.nasa.gov/learners
  44. http://www.mtu.edu/