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.

                                2021 March 12
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                                 Messier 81
                Image Credit & [3]Copyright: [4]Wissam Ayoub

   Explanation: One of the brightest galaxies in planet Earth's sky is
   similar in size to our Milky Way Galaxy: big, [5]beautiful Messier 81.
   Also known as NGC 3031 or Bode's galaxy for its 18th century
   discoverer, [6]this grand spiral can be found toward the northern
   constellation of Ursa Major, the Great Bear. [7]The sharp, detailed
   telescopic view reveals M81's bright yellow nucleus, blue spiral arms,
   pinkish starforming regions, and sweeping [8]cosmic dust lanes. Some
   dust lanes actually run through the galactic disk (left of center),
   contrary to other prominent [9]spiral features though. The [10]errant
   dust lanes may be the lingering result of a [11]close encounter between
   M81 and the nearby galaxy M82 lurking outside of this frame. M81's
   faint, dwarf irregular satellite galaxy, Holmberg IX, can be seen just
   below the large spiral. Scrutiny of variable stars in M81 has yielded a
   [12]well-determined distance for an external galaxy -- 11.8 million
   light-years.

                    Tomorrow's picture: one hand clapping
     __________________________________________________________________

      [13]< | [14]Archive | [15]Submissions | [16]Index | [17]Search |
   [18]Calendar | [19]RSS | [20]Education | [21]About APOD | [22]Discuss |
                                    [23]>
     __________________________________________________________________

    Authors & editors: [24]Robert Nemiroff ([25]MTU) & [26]Jerry Bonnell
                                 ([27]UMCP)
          NASA Official: Phillip Newman [28]Specific rights apply.
              [29]NASA Web Privacy Policy and Important Notices
                A service of: [30]ASD at [31]NASA / [32]GSFC
                           & [33]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2103/BodesGalaxyM81.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://www.astrobin.com/users/Wissam_Astrophotography/
   5. https://www.universetoday.com/47054/messier-81-1/
   6. https://www.nasa.gov/feature/goddard/2017/messier-81
   7. https://www.astrobin.com/c1jvyw/0/
   8. http://www.spitzer.caltech.edu/images/1070-ssc2003-06c-Spiral-Galaxy-Messier-81
   9. http://burro.astr.cwru.edu/Academics/Astr222/Galaxies/Spiral/spiral.html
  10. https://apod.nasa.gov/apod/ap010112.html
  11. https://apod.nasa.gov/apod/ap200515.html
  12. http://adsabs.harvard.edu/abs/1994ApJ...427..628F
  13. https://apod.nasa.gov/apod/ap210311.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=210312
  23. https://apod.nasa.gov/apod/ap210313.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. http://www.mtu.edu/