                        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.

                               2021 October 19

                      Palomar 6: Globular Star Cluster
                 Image Credit: ESA/Hubble and NASA, R. Cohen

   Explanation: Where did this big ball of stars come from? Palomar 6 is
   one of about 200 globular clusters of stars that survive in our Milky
   Way Galaxy. These spherical star-balls are older than our Sun as well
   as older than most stars that orbit in our galaxy's disk. Palomar 6
   itself is estimated to be about 12.5 billion years old, so old that it
   is close to -- and so constrains -- the age of the entire universe.
   Containing about 500,000 stars, Palomar 6 lies about 25,000 light years
   away, but not very far from our galaxy's center. At that distance, this
   sharp image from the Hubble Space Telescope spans about 15 light-years.
   After much study including images from Hubble, a leading origin
   hypothesis is that Palomar 6 was created -- and survives today -- in
   the central bulge of stars that surround the Milky Way's center, not in
   the distant galactic halo where most other globular clusters are now
   found.

                     Tomorrow's picture: lucy in the sky
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                             & Michigan Tech. U.


