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.

                               2023 January 20
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                          Galaxy Wars: M81 and M82
            Image Credit & [3]Copyright: [4]Andreas Aufschnaiter

   Explanation: The two dominant galaxies near center are far far away, 12
   million light-years distant toward the northern constellation of the
   Great Bear. On the right, with grand spiral arms and bright yellow core
   is [5]spiral galaxy M81. Also known as Bode's galaxy, M81 spans some
   100,000 light-years. On the left is cigar-shaped [6]irregular galaxy
   M82. The pair have been locked in gravitational combat for a billion
   years. [7]Gravity from each galaxy has profoundly affected the other
   during a series of cosmic close encounters. Their last go-round lasted
   about 100 million years and likely raised density waves rippling around
   M81, resulting in the richness of [8]M81's spiral arms. [9]M82 was left
   with violent star forming regions and colliding gas clouds so energetic
   that the galaxy [10]glows in X-rays. In the next few billion years,
   their continuing gravitational encounters will result in a merger, and
   a [11]single galaxy will remain. This extragalactic scenario also
   includes other members of the interacting [12]M81 galaxy group with NGC
   3077 below and right of the large spiral, and NGC 2976 at upper right
   in the frame. [13]Captured under dark night skies in the Austrian Alps,
   the foreground of the wide-field image is filled with integrated flux
   nebulae. Those faint, [14]dusty interstellar clouds reflect starlight
   above the plane of our own Milky Way galaxy.

                      Tomorrow's picture: light-weekend
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    Authors & editors: [26]Robert Nemiroff ([27]MTU) & [28]Jerry Bonnell
                                 ([29]UMCP)
          NASA Official: Phillip Newman [30]Specific rights apply.
              [31]NASA Web Privacy Policy and Important Notices
                A service of: [32]ASD at [33]NASA / [34]GSFC,
                         [35]NASA Science Activation
                           & [36]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2301/AUFSCHNAITER_Andreas_APOD_Bode_Cigare2048.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://www.instagram.com/aufschnaiter_photography/
   5. https://apod.nasa.gov/apod/ap190417.html
   6. https://apod.nasa.gov/apod/ap190723.html
   7. https://phys.org/news/2019-11-astronomers-stellar-halo.html
   8. http://www.youtube.com/watch?v=0seVq5ydqzk
   9. https://hubblesite.org/contents/news-releases/2001/news-2001-08.html
  10. https://chandra.harvard.edu/photo/2006/m82/
  11. https://science.nasa.gov/science-news/science-at-nasa/2012/31may_andromeda/
  12. http://www.atlasoftheuniverse.com/galgrps/m81.html
  13. https://www.instagram.com/p/CnSTIpuLZFV/
  14. https://apod.nasa.gov/apod/ap160428.html
  15. https://apod.nasa.gov/apod/ap230119.html
  16. https://apod.nasa.gov/apod/archivepix.html
  17. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  18. https://apod.nasa.gov/apod/lib/aptree.html
  19. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  20. https://apod.nasa.gov/apod/calendar/allyears.html
  21. https://apod.nasa.gov/apod.rss
  22. https://apod.nasa.gov/apod/lib/edlinks.html
  23. https://apod.nasa.gov/apod/lib/about_apod.html
  24. http://asterisk.apod.com/discuss_apod.php?date=230120
  25. https://apod.nasa.gov/apod/ap230121.html
  26. http://www.phy.mtu.edu/faculty/Nemiroff.html
  27. http://www.phy.mtu.edu/
  28. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  29. http://www.astro.umd.edu/
  30. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  31. https://www.nasa.gov/about/highlights/HP_Privacy.html
  32. https://astrophysics.gsfc.nasa.gov/
  33. https://www.nasa.gov/
  34. https://www.nasa.gov/centers/goddard/
  35. https://science.nasa.gov/learners
  36. http://www.mtu.edu/