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Birthday · January 22, 2011

Polar Ring Galaxy NGC 660

January 22, 2011

The cosmos is full of spectacular things: ringed planets, exploding suns, rivers of stars across the night.

Polar Ring Galaxy NGC 660

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APOD published January 22, 2011. Credit: Stephen Leshin. A publication-date match, not a photo taken on your date. Independent of NASA.

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Polar Ring Galaxy NGC 660

Original APOD · January 22, 2011

NGC 660 lies near the center of this intriguing skyscape, swimming in the boundaries of the constellation Pisces. 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 the galactic disk. The bizarre 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. Broader than the disk, NGC 660's ring spans about 40,000 light-years.

Image credit: Stephen Leshin

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