                        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 18
   A dark starfield has an unusual galaxy in the center. This galaxy has a
   spindle-like shape showing two dust lanes -- one running vertically and
   one running diagonally from the upper left. Please see the explanation
                       for more detailed information.

                         NGC 660: Polar Ring Galaxy
                    Image Credit & Copyright: Mike Selby

   Explanation: What kind of strange galaxy is this? This rare structure
   is known as a polar ring galaxy, and it seems to have two different
   rings of stars. In this galaxy, NGC 660, one ring of bright stars, gas,
   and dark dust appears nearly vertical, while another similar but
   shorter ring runs diagonally from the upper left. How polar ring
   galaxies obtain their striking appearance remains a topic of research,
   but a leading theory holds that it is usually the result of two
   galaxies with different central ring planes colliding. NGC 660 spans
   about 50,000 light years and is located about 40 million light years
   away toward the constellation of the Fish (Pisces). The featured image
   was captured recently from Observatorio El Sauce in Chile.

                       Tomorrow's picture: open space
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
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