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 January 10

         IFRAME: [2]https://www.youtube.com/embed/RtDSxi-D4KA?rel=0

                          Comet Leonard's Tail Wag
   Image Credit: [3]NASA, [4]NRL, [5]STEREO-A; Processing: [6]B. Gallagher

   Explanation: Why does Comet Leonard's tail wag? The [7]featured
   time-lapse video shows the ion tail of [8]Comet C/2021 A1 (Leonard) as
   it changed over ten days early last month. The video was taken by
   NASA's [9]Solar Terrestrial Relations Observatory-Ahead (STEREO-A)
   [10]spacecraft that [11]co-orbits the Sun at roughly the same distance
   as the Earth. Each image in this 29-degree field was subtracted from
   following image to create frames that highlight differences. The video
   clearly shows Comet Leonard's long ion tail extending, [12]wagging, and
   otherwise being [13]blown around by the [14]solar wind -- a stream of
   fast-moving [15]ions that stream out from the [16]Sun. Since the video
   was taken, [17]Comet Leonard continued plunging toward the Sun, reached
   its [18]closest approach to the Sun between the orbits of Mercury and
   Venus, survived this closest approach without [19]breaking apart, and
   is now fading as heads out of our [20]Solar System.

      Tuesday over Zoom: APOD editor to present the [21]Best APOD Space
                               Images of 2021
                      Tomorrow's picture: around orion
     __________________________________________________________________

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     __________________________________________________________________

    Authors & editors: [33]Robert Nemiroff ([34]MTU) & [35]Jerry Bonnell
                                 ([36]UMCP)
          NASA Official: Phillip Newman [37]Specific rights apply.
              [38]NASA Web Privacy Policy and Important Notices
                A service of: [39]ASD at [40]NASA / [41]GSFC
                           & [42]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://www.youtube.com/embed/RtDSxi-D4KA?rel=0
   3. https://www.nasa.gov/
   4. https://www.nrl.navy.mil/
   5. https://stereo.gsfc.nasa.gov/
   6. https://apod.nasa.gov/apod/
   7. https://stereo.gsfc.nasa.gov/news/cometleonard.shtml
   8. https://en.wikipedia.org/wiki/C/2021_A1_(Leonard)
   9. https://stereo.gsfc.nasa.gov/spacecraft.shtml
  10. https://en.wikipedia.org/wiki/STEREO
  11. https://stereo-ssc.nascom.nasa.gov/cgi-bin/make_where_gif
  12. https://apod.nasa.gov/apod/ap131123.html
  13. https://apod.nasa.gov/apod/ap071003.html
  14. https://solarsystem.nasa.gov/resources/2288/the-solar-wind-across-our-solar-system/
  15. https://en.wikipedia.org/wiki/Ion
  16. https://apod.nasa.gov/apod/ap180916.html
  17. https://www.facebook.com/media/set/?set=a.4214632848640902&type=3
  18. https://en.wikipedia.org/wiki/C/2021_A1_(Leonard)#/media/File:Animation_of_C／2021_A1's_orbit_around_Sun_-_2021_close_approach.gif
  19. https://apod.nasa.gov/apod/ap060504.html
  20. https://solarsystem.nasa.gov/solar-system/our-solar-system/in-depth/
  21. https://aaa.org/event/astronomy-picture-of-the-day-2/
  22. https://apod.nasa.gov/apod/ap220109.html
  23. https://apod.nasa.gov/apod/archivepix.html
  24. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  25. https://apod.nasa.gov/apod/lib/aptree.html
  26. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  27. https://apod.nasa.gov/apod/calendar/allyears.html
  28. https://apod.nasa.gov/apod.rss
  29. https://apod.nasa.gov/apod/lib/edlinks.html
  30. https://apod.nasa.gov/apod/lib/about_apod.html
  31. http://asterisk.apod.com/discuss_apod.php?date=220110
  32. https://apod.nasa.gov/apod/ap220111.html
  33. http://www.phy.mtu.edu/faculty/Nemiroff.html
  34. http://www.phy.mtu.edu/
  35. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  36. http://www.astro.umd.edu/
  37. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  38. https://www.nasa.gov/about/highlights/HP_Privacy.html
  39. https://astrophysics.gsfc.nasa.gov/
  40. https://www.nasa.gov/
  41. https://www.nasa.gov/centers/goddard/
  42. http://www.mtu.edu/