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80 Million Light-Years From Earth

Image credit: ESA/Hubble & NASA, J. Walsh; Acknowledgment: R. Colombari

European Space Agency (ESA)

The lazily winding spiral arms of the galaxy NGC 5921 snake across this image from the NASA/ESA Hubble Space Telescope. This galaxy lies approximately 80 million light-years from Earth, and much like our own galaxy, the Milky Way, contains a prominent bar – a central linear band of stars. Roughly half of all spiral galaxies may contain bars. These bars affect their parent galaxies by fueling star formation and influencing the motion of stars and interstellar gas.

Given NGC 5921’s serpentine spiral arms, it seems fitting that the galaxy resides in the constellation Serpens in the northern celestial hemisphere. Serpens is the only one of the 88 modern constellations with two unconnected regions – Serpens Caput (Serpent’s Head) and Serpens Cauda (Serpent’s Tail). Ophiuchus, the Serpent Bearer, separates these two regions.

The scientific study behind this image also came in two parts – observations from Hubble’s Wide Field Camera 3 and observations from the ground-based Gemini Observatory. The two telescopes helped astronomers better understand the relationship between galaxies like NGC 5921 and the supermassive black holes they contain. Hubble’s contribution determined the masses of stars in the galaxies. Hubble also took measurements that helped calibrate the observations from Gemini. Together, Hubble and Gemini provided astronomers with a census of nearby supermassive black holes in a diverse variety of galaxies.

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