Astronomy Picture of the Day

    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 May 15

                          Galaxy Wars: M81 and M82
         Image Credit & Copyright: Dietmar Hager, Torsten Grossmann

   Explanation: These two galaxies are far far away, 12 million
   light-years distant toward the northern constellation of the Great
   Bear. On the left, with grand spiral arms and bright yellow core is
   spiral galaxy M81, some 100,000 light-years across. On the right marked
   by red gas and dust clouds, is irregular galaxy M82. The pair have been
   locked in gravitational combat for a billion years. 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 M81's spiral arms. M82 was left with violent star forming
   regions and colliding gas clouds so energetic the galaxy glows in
   X-rays. In the next few billion years, their continuing gravitational
   encounters will result in a merger, and a single galaxy will remain.

                      Tomorrow's picture: light-weekend
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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