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.

                               2023 February 9
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                        Nacreous Clouds over Lapland
               Image Credit & [3]Copyright: [4]Dennis Lehtonen

   Explanation: Vivid and lustrous, wafting iridescent waves of color wash
   across this skyscape from Kilpisjärvi, Finland. [5]Known as nacreous
   clouds or mother-of-pearl clouds, they are rare. But their
   [6]unforgettable appearance was captured looking south at 69 degrees
   north latitude at sunset on January 24. A type of [7]polar
   stratospheric cloud, they form when unusually cold temperatures in the
   usually cloudless [8]lower stratosphere form ice crystals. Still sunlit
   at altitudes of around 15 to 25 kilometers, the clouds can diffract
   sunlight even after sunset and just before the dawn.

                     Tomorrow's picture: pixels in space
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    Authors & editors: [20]Robert Nemiroff ([21]MTU) & [22]Jerry Bonnell
                                 ([23]UMCP)
          NASA Official: Phillip Newman [24]Specific rights apply.
              [25]NASA Web Privacy Policy and Important Notices
                A service of: [26]ASD at [27]NASA / [28]GSFC,
                         [29]NASA Science Activation
                           & [30]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2302/PearlCloudDennis7.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://www.instagram.com/astrodenniina/
   5. https://www.atoptics.co.uk/highsky/nacr1.htm
   6. https://ui.adsabs.harvard.edu/abs/2018BAMS...99.1377P/abstract
   7. https://www.nasa.gov/multimedia/imagegallery/image_feature_680.html
   8. https://www.atoptics.co.uk/highsky/htrop.htm
   9. https://apod.nasa.gov/apod/ap230208.html
  10. https://apod.nasa.gov/apod/archivepix.html
  11. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  12. https://apod.nasa.gov/apod/lib/aptree.html
  13. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  14. https://apod.nasa.gov/apod/calendar/allyears.html
  15. https://apod.nasa.gov/apod.rss
  16. https://apod.nasa.gov/apod/lib/edlinks.html
  17. https://apod.nasa.gov/apod/lib/about_apod.html
  18. http://asterisk.apod.com/discuss_apod.php?date=230209
  19. https://apod.nasa.gov/apod/ap230210.html
  20. http://www.phy.mtu.edu/faculty/Nemiroff.html
  21. http://www.phy.mtu.edu/
  22. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  23. http://www.astro.umd.edu/
  24. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  25. https://www.nasa.gov/about/highlights/HP_Privacy.html
  26. https://astrophysics.gsfc.nasa.gov/
  27. https://www.nasa.gov/
  28. https://www.nasa.gov/centers/goddard/
  29. https://science.nasa.gov/learners
  30. http://www.mtu.edu/