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.

                               2020 January 27
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                             Comet CG Evaporates
            Image Credit & [3]License: [4]ESA, [5]Rosetta, NAVCAM

   Explanation: Where do comet tails come from? There are no obvious
   places on the [6]nuclei of comets from which the [7]jets that create
   [8]comet tails emanate. One of the best images of emerging jets is
   shown in the [9]featured picture, taken in 2015 by ESA's robotic
   [10]Rosetta spacecraft that orbited [11]Comet 67P/Churyumov-Gerasimenko
   (Comet CG) from 2014 to 2016. The picture shows plumes of gas and dust
   escaping numerous places from [12]Comet CG's nucleus as it neared
   [13]the Sun and heated up. The comet has two prominent lobes, the
   larger one spanning about 4 kilometers, and a smaller 2.5-kilometer
   lobe connected by a narrow neck. Analyses indicate that [14]evaporation
   must be taking place well inside the comet's surface to create the
   [15]jets of dust and ice that we see emitted through the surface.
   [16]Comet CG (also known as Comet 67P) loses in jets about a meter of
   radius during each of its 6.44-year orbits around the Sun, a rate at
   which will completely destroy the comet in only thousands of years. In
   2016, [17]Rosetta's [18]mission ended with a controlled impact onto
   Comet CG's surface.

            Outreach Astronomers: [19]Future APOD writers sought.
                      Tomorrow's picture: a tad spacey
     __________________________________________________________________

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    Authors & editors: [31]Robert Nemiroff ([32]MTU) & [33]Jerry Bonnell
                                 ([34]UMCP)
          NASA Official: Phillip Newman [35]Specific rights apply.
              [36]NASA Web Privacy Policy and Important Notices
                A service of: [37]ASD at [38]NASA / [39]GSFC
                           & [40]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2001/Comet67P_Rosetta_1024.jpg
   3. https://creativecommons.org/licenses/by-sa/3.0/igo/
   4. https://www.esa.int/
   5. http://rosetta.esa.int/
   6. http://www.planetary.org/multimedia/space-images/small-bodies/comets-visited-by-spacecraft-2014.html
   7. https://apod.nasa.gov/apod/ap150203.html
   8. https://apod.nasa.gov/apod/ap000413.html
   9. http://www.esa.int/ESA_Multimedia/Images/2015/03/Comet_on_25_February_2015_NavCam
  10. http://www.esa.int/Science_Exploration/Space_Science/Rosetta/Europe_s_comet_chaser
  11. https://en.wikipedia.org/wiki/67P/Churyumov–Gerasimenko
  12. https://apod.nasa.gov/apod/ap171106.html
  13. https://solarsystem.nasa.gov/solar-system/sun/in-depth/
  14. https://www.youtube.com/watch?v=BHmUx0ylg-A
  15. https://commons.wikimedia.org/wiki/File:67P_Churyumov-Gerasimenko_surface.gif
  16. https://apod.nasa.gov/apod/ap160202.html
  17. https://www.nasa.gov/rosetta
  18. https://apod.nasa.gov/apod/ap161001.html
  19. https://asterisk.apod.com/viewtopic.php?f=28&t=40229
  20. https://apod.nasa.gov/apod/ap200126.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.nasa.gov/apod.rss
  27. https://apod.nasa.gov/apod/lib/edlinks.html
  28. https://apod.nasa.gov/apod/lib/about_apod.html
  29. http://asterisk.apod.com/discuss_apod.php?date=200127
  30. https://apod.nasa.gov/apod/ap200128.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://astrophysics.gsfc.nasa.gov/
  38. https://www.nasa.gov/
  39. https://www.nasa.gov/centers/goddard/
  40. http://www.mtu.edu/