NGC 660 is near the center of this photo which is in the boundaries of the constellation Pisces. It is over 20 million light-years away and it has a peculiar appearance because it is a polar ring galaxy. These galaxies are rare and have substantial populations of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of the galactic disk. It is postulated that the configuration could have been caused by the chance capture of material from a passing galaxy by the disk galaxy, with the captured debris strung out in a rotating ring. The polar ring component 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. NGC 660's ring spans about 40,000 light-years.
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