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 April 4
      [2]The featured image depicts a bright aurora that occurred over
     Iceland in March. The curvature of the aurora makes it look like a
      vortex. Please see the explanation for more detailed information.

                        A Vortex Aurora over Iceland
               Image Credit & Copyright: [3]Christophe Suarez

   Explanation: No, the car was not in danger of being vacuumed into space
   by the big sky vortex. For one reason, the vortex was really an
   [4]aurora, and since auroras are created by particles striking the
   Earth from space, they do not create a [5]vacuum. This rapidly
   [6]developing auroral display was caused by a [7]Coronal Mass Ejection
   from the Sun that passed by the Earth closely enough to cause a ripple
   in [8]Earth's magnetosphere. The [9]upper red parts of the aurora occur
   over 250 kilometers high with its red [10]glow created by atmospheric
   atomic oxygen directly energized by incoming particles. The [11]lower
   green parts of the [12]aurora occur over 100 kilometers high with its
   green [13]glow created by atmospheric [14]atomic oxygen energized
   indirectly by collisions with first-energized [15]molecular nitrogen.
   Below 100 kilometers, there is little atomic oxygen, which is why
   auroras end abruptly. The [16]concentric [17]cylinders depict a
   [18]dramatic auroral [19]corona as seen from the side. The featured
   image was created from a single 3-second exposure taken in mid-March
   over [20]Lake Myvat[21]n in [22]Iceland.

                    April is: [23]Global Astronomy Month
                    Tomorrow's picture: california seven
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    Authors & editors: [35]Robert Nemiroff ([36]MTU) & [37]Jerry Bonnell
                                 ([38]UMCP)
          NASA Official: Phillip Newman [39]Specific rights apply.
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                A service of: [41]ASD at [42]NASA / [43]GSFC
                           & [44]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2204/VortexAurora_Suarez_1920.jpg
   3. mailto: Christof dot suarez at gmail dot com
   4. https://spaceplace.nasa.gov/aurora/en/
   5. https://www.nasa.gov/offices/setmo/facilities/thermal_vacuum_chamber_a
   6. https://spaceweather.com/archive.php?view=1&day=20&month=03&year=2022
   7. https://www.nasa.gov/content/goddard/what-is-a-coronal-mass-ejection
   8. https://www.nasa.gov/magnetosphere
   9. https://apod.nasa.gov/apod/ap220220.html
  10. https://aurora.live/2020/04/aurora-borealis-colors-explained/
  11. https://apod.nasa.gov/apod/ap210114.html
  12. https://svs.gsfc.nasa.gov/4934
  13. https://en.wikipedia.org/wiki/Aurora#Colors_and_wavelengths_of_auroral_light
  14. https://manoa.hawaii.edu/exploringourfluidearth/chemical/chemistry-and-seawater/atoms-and-molecules
  15. https://en.wikipedia.org/wiki/Molecule
  16. https://mathworld.wolfram.com/ConcentricCircles.html
  17. https://en.wikipedia.org/wiki/Cylinder
  18. https://img.huffingtonpost.com/asset/5bad12683c000032000b0e42.jpeg?ops=scalefit_720_noupscale
  19. https://apod.nasa.gov/apod/ap141014.html
  20. https://youtu.be/kgQaU1of50Q
  21. https://en.wikipedia.org/wiki/Mývatn
  22. https://en.wikipedia.org/wiki/Iceland
  23. https://www.astronomerswithoutborders.org/programs/global-astronomy-month
  24. https://apod.nasa.gov/apod/ap220403.html
  25. https://apod.nasa.gov/apod/archivepix.html
  26. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  27. https://apod.nasa.gov/apod/lib/aptree.html
  28. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  29. https://apod.nasa.gov/apod/calendar/allyears.html
  30. https://apod.nasa.gov/apod.rss
  31. https://apod.nasa.gov/apod/lib/edlinks.html
  32. https://apod.nasa.gov/apod/lib/about_apod.html
  33. http://asterisk.apod.com/discuss_apod.php?date=220404
  34. https://apod.nasa.gov/apod/ap220405.html
  35. http://www.phy.mtu.edu/faculty/Nemiroff.html
  36. http://www.phy.mtu.edu/
  37. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  38. http://www.astro.umd.edu/
  39. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  40. https://www.nasa.gov/about/highlights/HP_Privacy.html
  41. https://astrophysics.gsfc.nasa.gov/
  42. https://www.nasa.gov/
  43. https://www.nasa.gov/centers/goddard/
  44. http://www.mtu.edu/