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 March 11
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                             When Rainbows Smile
            Image Credit & [3]Copyright: [4]Marcella Giulia Pace

   Explanation: [5]Want to see a rainbow smile? Look near the zenith
   (straight up) when the sun is low in the sky and you might. This
   example of an [6]ice halo known as a circumzenithal arc was captured
   above a palm tree top from Ragusa, Sicily on February 24. The vividly
   colorful arcs are often called smiling rainbows because of their upside
   down curvature and colors. For [7]circumzenithal arcs the [8]zenith is
   at the center and red is on the outside, compared to rainbows whose
   arcs [9]bend toward the horizon after a downpour. True rainbows are
   formed by water droplets refracting the sunlight to produce a spectrum
   of colors, [10]though. Circumzenithal arcs are the product of
   [11]refraction and reflection in flat hexagonal ice crystals, like the
   ice crystals that create sundogs, formed in high thin clouds.

                       Tomorrow's picture: winging it
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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/2203/ArcoCircumzenitale.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://greenflash.photo/about-me/
   5. https://greenflash.photo/greenflash-gallery/greenflash-gallery/portfolio/circumzenithal-arc/#lightbox[group]/24/
   6. https://apod.nasa.gov/apod/ap181221.html
   7. https://www.atoptics.co.uk/halo/cza.htm
   8. https://www.atoptics.co.uk/halo/czasalt.htm
   9. https://apod.nasa.gov/apod/ap100807.html
  10. https://www.nasa.gov/feature/episode-20-we-asked-a-nasa-scientist-are-there-rainbows-on-mars
  11. http://iapetus.jb.man.ac.uk/cza/CZA.html
  12. https://apod.nasa.gov/apod/ap220310.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=220311
  22. https://apod.nasa.gov/apod/ap220312.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/