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.

                               2026 August 27
     [2]A night view of a waterfall with a colorful aurora in shades of
         green, yellow, red and purple, and stars in the background.

                  Colorful Aurora over Icelandic Waterfall
                  Image Credit & Copyright: [3]Victor Lima
     Text: [4]Cecilia Chirenti ([5]NASA [6]GSFC, [7]UMCP, [8]CRESST II)

   Explanation: What a sight to behold, when a night sky became filled
   with colors that appeared to rain over the Skógafoss waterfall in
   Iceland. This image was taken in a single [9]5 second exposure by the
   photographer in April 2025. Seeing an [10]aurora is on many people's
   bucket lists. But it is not easy. It requires high [11]solar activity,
   dark and clear skies, and usually a viewing location at high latitude.
   That makes the northern lights more easily seen than the corresponding
   [12]southern lights, simply because there is less landmass in the
   Southern Hemisphere, especially [13]around the Antarctic Circle.
   Auroras are caused by charged particles from the [14]solar wind that
   are captured by the Earth's [15]magnetosphere and guided by the
   magnetic field to a region close to one of the poles, where they
   collide with gas particles in the [16]atmosphere. Different colors
   indicate interactions with different gases at [17]different altitudes,
   like oxygen ([18]red and [19]green) and nitrogen ([20]blue and
   [21]pink).

       APOD's main NASA site is [22]moving : From [23]apod.nasa.gov to
                          [24]science.nasa.gov/apod
                      Tomorrow's picture: What's next?
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    Authors & editors: [36]Robert Nemiroff ([37]MTU) & [38]Jerry Bonnell
                                 ([39]UMCP)
          NASA Official: Amber Straughn [40]Specific rights apply.
            [41]NASA Web Privacy, [42]Accessibility, [43]Notices;
                A service of: [44]ASD at [45]NASA / [46]GSFC,
                         [47]NASA Science Activation
                           & [48]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2608/Aurora_over_Fall.jpg
   3. https://www.trilhadeestrelas.com/
   4. https://science.gsfc.nasa.gov/sci/bio/cecilia.chirenti
   5. https://www.nasa.gov/
   6. https://www.nasa.gov/goddard/
   7. https://www.astro.umd.edu/people/cecilia-chirenti
   8. https://cresst2.umd.edu/
   9. https://www.instagram.com/p/DcBX5OcTMqH/
  10. https://science.nasa.gov/sun/auroras/
  11. https://www.spaceweather.gov/products/solar-cycle-progression
  12. https://apod.nasa.gov/apod/ap240913.html
  13. https://assets.science.nasa.gov/dynamicimage/assets/science/cds/kids/nasa-kids-science/earth/which-pole-is-colder/south-pole.png
  14. https://science.nasa.gov/resource/the-solar-wind-across-our-solar-system/
  15. https://science.nasa.gov/science-research/earth-science/earths-magnetosphere-protecting-our-planet-from-harmful-space-energy/
  16. https://www.nasa.gov/general/what-is-earths-atmosphere/
  17. https://assets.science.nasa.gov/dynamicimage/assets/science/hpd/itm/what-gives-aurora-colors.png
  18. https://apod.nasa.gov/apod/ap240512.html
  19. https://apod.nasa.gov/apod/ap240522.html
  20. https://apod.nasa.gov/apod/ap241223.html
  21. https://apod.nasa.gov/apod/ap120725.html
  22. https://asterisk.apod.com/viewtopic.php?t=45023
  23. https://apod.nasa.gov/
  24. https://science.nasa.gov/apod
  25. https://apod.nasa.gov/apod/ap260826.html
  26. https://apod.nasa.gov/apod/archivepix.html
  27. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  28. https://apod.nasa.gov/apod/lib/aptree.html
  29. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  30. https://apod.nasa.gov/apod/calendar/allyears.html
  31. https://apod.com/feed.rss
  32. https://apod.nasa.gov/apod/lib/edlinks.html
  33. https://apod.nasa.gov/apod/lib/about_apod.html
  34. https://asterisk.apod.com/discuss_apod.php?date=260827
  35. https://apod.nasa.gov/apod/ap260828.html
  36. https://www.mtu.edu/physics/department/faculty/nemiroff/
  37. https://www.mtu.edu/physics/
  38. https://inspirehep.net/authors/1073087
  39. http://www.astro.umd.edu/
  40. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  41. https://www.nasa.gov/about/highlights/HP_Privacy.html
  42. https://www.nasa.gov/general/accessibility/
  43. https://www.nasa.gov/privacy/
  44. https://science.gsfc.nasa.gov/astrophysics/
  45. https://www.nasa.gov/
  46. https://www.nasa.gov/centers/goddard/
  47. https://science.nasa.gov/learn/about-science-activation/
  48. http://www.mtu.edu/