                        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.

                                2025 July 14
   An unusual galaxy is shown that appears lens-like in overall shape yet
        has various rings of stars around the center. Please see the
                 explanation for more detailed information.

                         NGC 2685: The Helix Galaxy
                   Image Credit & Copyright: Stefan Thrun

   Explanation: What is going on with this galaxy? NGC 2685 is a confirmed
   polar ring galaxy - a rare type of galaxy with stars, gas and dust
   orbiting in rings perpendicular to the plane of a flat galactic disk.
   The bizarre configuration could be caused by the chance capture of
   material from another galaxy by a disk galaxy, with the captured debris
   strung out in a rotating ring. Still, observed properties of NGC 2685
   suggest that the rotating helix structure is remarkably old and stable.
   In this sharp view of the peculiar system also known as Arp 336 or the
   Helix galaxy, the strange, perpendicular rings are easy to trace as
   they pass in front of the galactic disk, along with other disturbed
   outer structures. NGC 2685 is about 50,000 light-years across and 40
   million light-years away in the constellation of the Great Bear (Ursa
   Major).

             Piece it All Together: Astronomy Puzzle of the Day
                    Tomorrow's picture: collapse on Mars
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