                        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.

                              2024 December 19

                                  Messier 2
              Image Credit: ESA/Hubble & NASA, G. Piotto et al.

   Explanation: After the Crab Nebula, this giant star cluster is the
   second entry in 18th century astronomer Charles Messier's famous list
   of things that are not comets. M2 is one of the largest globular star
   clusters now known to roam the halo of our Milky Way galaxy. Though
   Messier originally described it as a nebula without stars, this
   stunning Hubble image resolves stars across the cluster's central 40
   light-years. Its population of stars numbers close to 150,000,
   concentrated within a total diameter of around 175 light-years. About
   55,000 light-years distant toward the constellation Aquarius, this
   ancient denizen of the Milky Way, also known as NGC 7089, is 13 billion
   years old. An extended stellar debris stream, a signature of past
   gravitational tidal disruption, was recently found to be associated
   with Messier 2.

                   Tomorrow's picture: the last full moon
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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