Polar Ring Galaxy NGC 660 . ... Over 20 million light-years away, its peculiar appearance marks it as a polar ring galaxy . A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of a flat galactic disk. ... Polar Ring galaxies can be used to explore the shape of the galaxy's otherwise unseen dark matter halo by calculating the dark matter's gravitational influence on the rotation of the ring and disk. ...