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.

                                2025 April 10
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                         38 Hours with the M81 Group
               Image Credit & [3]Copyright: [4]Daniel Yang K.

   Explanation: From a garden on planet Earth, 38 hours of exposure with a
   camera and small telescope produced [5]this cosmic photo of the M81
   galaxy group. In fact, the group's dominant galaxy M81 is near the
   center of the frame sporting grand spiral arms and a bright yellow
   core. Also known as Bode's galaxy, M81 itself spans some 100,000
   light-years. Near the top 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 massive star forming regions arrayed along [8]M81's spiral
   arms. [9]M82 was left with violent star forming regions too, 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. Another group member, NGC 3077 is below and left of the large
   spiral M81. Far far away, about 12 million light-years distant the M81
   group galaxies are seen toward the northern constellation Ursa Major
   (the Great Bear). But in the closer foreground the wide-field image is
   filled with integrated flux nebulae whose faint, [12]dusty interstellar
   clouds reflect starlight above the plane of our own Milky Way galaxy.

                        Tomorrow's picture: a matinee
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    Authors & editors: [24]Robert Nemiroff ([25]MTU) & [26]Jerry Bonnell
                                 ([27]UMCP)
          NASA Official: Amber Straughn [28]Specific rights apply.
              [29]NASA Web Privacy Policy and Important Notices
                A service of: [30]ASD at [31]NASA / [32]GSFC,
                         [33]NASA Science Activation
                           & [34]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2504/38h_M81-group_Jpeg.jpeg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://app.astrobin.com/u/Daniel_Yang_K.#gallery
   5. https://app.astrobin.com/u/Daniel_Yang_K.?i=ldzdz7#gallery
   6. https://apod.nasa.gov/apod/ap190723.html
   7. https://phys.org/news/2019-11-astronomers-stellar-halo.html
   8. https://apod.nasa.gov/apod/ap250327.html
   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/asset/hubble/collision-scenario-for-milky-way-and-andromeda-galaxy-encounter/
  12. https://apod.nasa.gov/apod/ap160428.html
  13. https://apod.nasa.gov/apod/ap250409.html
  14. https://apod.nasa.gov/apod/archivepix.html
  15. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  16. https://apod.nasa.gov/apod/lib/aptree.html
  17. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  18. https://apod.nasa.gov/apod/calendar/allyears.html
  19. https://apod.nasa.gov/apod.rss
  20. https://apod.nasa.gov/apod/lib/edlinks.html
  21. https://apod.nasa.gov/apod/lib/about_apod.html
  22. http://asterisk.apod.com/discuss_apod.php?date=250410
  23. https://apod.nasa.gov/apod/ap250411.html
  24. http://www.phy.mtu.edu/faculty/Nemiroff.html
  25. http://www.phy.mtu.edu/
  26. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  27. http://www.astro.umd.edu/
  28. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  29. https://www.nasa.gov/about/highlights/HP_Privacy.html
  30. https://astrophysics.gsfc.nasa.gov/
  31. https://www.nasa.gov/
  32. https://www.nasa.gov/centers/goddard/
  33. https://science.nasa.gov/learners
  34. http://www.mtu.edu/