The Whirlpool Galaxy (M51) is ideal for Northern Hemisphere viewers. It is visible through binoculars in dark conditions, as well as with amateur telescopes. This galaxy is a spiral galaxy about 15-35 million light years away and was actually the first galaxy to be identified as a spiral galaxy! It is 35 percent the size of the Milky Way. As seen in the processed picture below, M51 has a dwarf galaxy sharing material with the spiral galaxy, known as NGC 5195. This dwarf galaxy passed through the main disk of M51 about 500 to 600 million years ago. It was predicted that NGC 5195 came from behind M51 and passed through the main disk, then again making another disk crossing anywhere from 50 to 100 million years ago. Now it is located where it can be seen now a little bit behind M51. This dynamic duo is studied specifically for galaxy structure. It is expected that the center of M51 is a black hole surrounded by rings of dust. These secondary rings cross the primary rings of the spiral nebula on a different axis, this is a phenomenon as it is unique from many studied spiral galaxies. Ionization cones (emission of photons from nuclear activity in the galaxy) extend out from the primary rings of the spiral galaxy. Star formation is strongly active in the center of the galaxy as well. It’s center is currently undergoing a period of enhanced star formation. This high rate cannot last more than 100 million years. This high pressure of hydrogen from stars can be seen in the bright blue knots in the spiral arms.
History: The Whirlpool galaxy was discovered by Charles Messier on October 13, 1773 and NGC 5195 was discovered in 1981 by Pierre Me’chain. However in 1855 William Parsons discovered the Whirlpool galaxy’s spiral structure, which made it the first ‘nebula’ (what people called galaxies in the past) known to have that structure. https://en.wikipedia.org/wiki/Ionization_cone https://en.wikipedia.org/wiki/Whirlpool_Galaxy
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AuthorPassionante amateur astronomer| 18| Pomfret '17| BU '21 |