Présentation(Wikipédia)

Ses bras spiraux facilement visibles lui ont valu son surnom de « galaxie tourbillon » (

The Whirlpool Galaxy, also known as Messier 51a, M51a, or NGC 5194, is an interacting[7] grand-design[8] spiral galaxy with a Seyfert 2 active galactic nucleus[9] in the constellation Canes Venatici. In the Catalogue of Named Galaxies, it is called Typhon Canum Venaticorum, after the Greek god Typhon.[10] It was the first galaxy to be classified as a spiral galaxy.[11] Recently it was estimated to be 23 ± 4 million light-years from the Milky Way,[3] but different methods yield distances between 15 and 35 million light-years. Messier 51 is one of the best known galaxies in the sky.[12] The galaxy and its companion, NGC 5195,[13] are easily observed by amateur astronomers, and the two galaxies may even be seen with binoculars.[14] The Whirlpool Galaxy is also a popular target for professional astronomers, who study it to further understand galaxy structure (particularly structure associated with the spiral arms) and galaxy interactions