                        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 January 25

                               Rubin's Galaxy
       Image Credit: NASA, ESA, B. Holwerda (University of Louisville)

   Explanation: In this Hubble Space Telescope image the bright, spiky
   stars lie in the foreground toward the heroic northern constellation
   Perseus and well within our own Milky Way galaxy. In sharp focus beyond
   is UGC 2885, a giant spiral galaxy about 232 million light-years
   distant. Some 800,000 light-years across compared to the Milky Way's
   diameter of 100,000 light-years or so, it has around 1 trillion stars.
   That's about 10 times as many stars as the Milky Way. Part of a current
   investigation to understand how galaxies can grow to such enormous
   sizes, UGC 2885 was also part of astronomer Vera Rubin's pioneering
   study of the rotation of spiral galaxies. Her work was the first to
   convincingly demonstrate the dominating presence of dark matter in our
   universe.

                      Tomorrow's picture: Rubin's ridge
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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.

