                        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 August 6

                              Messier 20 and 21
                 Image Credit & Copyright: Emanuele Petrilli

   Explanation: The beautiful Trifid Nebula, also known as Messier 20, is
   easy to find with a small telescope in the nebula rich constellation
   Sagittarius. About 5,000 light-years away, the colorful study in cosmic
   contrasts shares this well-composed, nearly 1 degree wide field with
   open star cluster Messier 21 (right). Trisected by dust lanes the
   Trifid itself is about 40 light-years across and a mere 300,000 years
   old. That makes it one of the youngest star forming regions in our sky,
   with newborn and embryonic stars embedded in its natal dust and gas
   clouds. Estimates of the distance to open star cluster M21 are similar
   to M20's, but though they share this gorgeous telescopic skyscape there
   is no apparent connection between the two. In fact, M21's stars are
   much older, about 8 million years old.

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