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 December 23
   [2]A star filled night sky is shown with aurora visible in blue, purple
   and green. The aurora could be perceived to be a spruce tree, or even a
        Christmas tree. Please see the explanation for more detailed
                                information.

                            Christmas Tree Aurora
                  Image Credit & Copyright: [3]Jingyi Zhang

   Explanation: It was December and the sky lit up like a Christmas tree.
   Shimmering, the vivid green, blue, and purple [4]auroral colors that
   formed the tree-like apparition were caused by high atmospheric
   [5]oxygen and [6]nitrogen reacting to a burst of incoming electrons.
   Collisions caused the orbital [7]electrons of atoms and molecules to
   [8]jump into excited energy states and emit [9]visible light when
   returning to their normal state. The featured image was captured in
   [10]Djúpivogur, [11]Iceland during the last month of 2023. Our [12]Sun
   is currently in its [13]most energetic phase of its 11-year cycle, with
   its high number of [14]active regions and sunspots likely to last into
   next year. Of course, the Sun has been near [15]solar maximum during
   this entire year, with its [16]outbursts sometimes resulting in
   [17]spectacular Earthly [18]auroras.

           Image Processors: Take NASA's [19]Astrophoto Challenge
                        Tomorrow's picture: star tree
     __________________________________________________________________

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    Authors & editors: [31]Robert Nemiroff ([32]MTU) & [33]Jerry Bonnell
                                 ([34]UMCP)
          NASA Official: Amber Straughn [35]Specific rights apply.
            [36]NASA Web Privacy, [37]Accessibility, [38]Notices;
                A service of: [39]ASD at [40]NASA / [41]GSFC,
                         [42]NASA Science Activation
                           & [43]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2412/AuroraTree_Zhang_1537.jpg
   3. mailto:jingyi .dot. tia .dot. zhang @at@ gmail .d.o.t. com
   4. https://svs.gsfc.nasa.gov/vis/a000000/a004900/a004934/Different_Colors_of_Auroras.pdf
   5. https://periodic.lanl.gov/8.shtml
   6. https://periodic.lanl.gov/7.shtml
   7. https://www.aps.org/apsnews/2000/10/discovery-of-the-electron
   8. https://www.youtube.com/shorts/m3C7Pv9u2l0
   9. https://science.nasa.gov/ems/09_visiblelight/
  10. https://youtu.be/nDxwPAyCXK4
  11. https://en.wikipedia.org/wiki/Iceland
  12. https://science.nasa.gov/sun/
  13. https://science.nasa.gov/science-research/heliophysics/nasa-noaa-sun-reaches-maximum-phase-in-11-year-solar-cycle/
  14. https://apod.nasa.gov/apod/ap141022.html
  15. https://en.wikipedia.org/wiki/Solar_maximum
  16. https://apod.nasa.gov/apod/ap240818.html
  17. http://funkot.ru/wp-content/uploads/2013/12/kotik-v-shapochke.jpg
  18. https://apod.nasa.gov/apod/ap240612.html
  19. https://universe-of-learning.org/resources/projects/nasas-astrophoto-challenge
  20. https://apod.nasa.gov/apod/ap241222.html
  21. https://apod.nasa.gov/apod/archivepix.html
  22. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  23. https://apod.nasa.gov/apod/lib/aptree.html
  24. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  25. https://apod.nasa.gov/apod/calendar/allyears.html
  26. https://apod.com/feed.rss
  27. https://apod.nasa.gov/apod/lib/edlinks.html
  28. https://apod.nasa.gov/apod/lib/about_apod.html
  29. https://asterisk.apod.com/discuss_apod.php?date=241223
  30. https://apod.nasa.gov/apod/ap241224.html
  31. http://www.phy.mtu.edu/faculty/Nemiroff.html
  32. http://www.phy.mtu.edu/
  33. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  34. http://www.astro.umd.edu/
  35. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  36. https://www.nasa.gov/about/highlights/HP_Privacy.html
  37. https://www.nasa.gov/general/accessibility/
  38. https://www.nasa.gov/privacy/
  39. https://astrophysics.gsfc.nasa.gov/
  40. https://www.nasa.gov/
  41. https://www.nasa.gov/centers/goddard/
  42. https://science.nasa.gov/learners
  43. http://www.mtu.edu/