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Spiral galaxy m516/19/2023 ![]() Astronomers believe that it is also triggering waves of new star formation. The tidal interaction with NGC 5195, which was not discovered until the advent of radio astronomy, has considerably enhanced the spiral structure of the Whirlpool Galaxy. The bridge is visible in images of the pair silhouetted against the central region of the smaller galaxy. The Whirlpool Galaxy is interacting with a smaller companion, NGC 5195 (Messier 51b), a dwarf galaxy connected to its larger neighbour by a tidal bridge of dust. Messier 51 is classified as a Seyfert 2 galaxy, an active galaxy with a quasar-like nucleus, a very high surface brightness and a characteristic bright core, one that appears particularly bright at infrared wavelengths. The Whirlpool Galaxy is the brightest member of the M51 Group, a relatively small group of galaxies that also includes the famous Sunflower Galaxy (M63) and the fainter edge-on spirals NGC 5023 and NGC 5229. It wasn’t until the 1920s, when Edwin Hubble proved that “spiral nebulae” were in fact distant galaxies, that Whirlpool and other objects of this type were recognized as independent galaxies and not nebulae inside the Milky Way. He also made a very accurate painting of the “spiral nebula” and, for this reason, the galaxy is sometimes known as Lord Rosse’s Question Mark. Lord Rosse used his 72-inch reflector at Birr Castle in Ireland to observe M51 when he made the discovery. The Whirlpool Galaxy is also known as the Question Mark Galaxy or Rosse’s Galaxy, after William Parsons, 3rd Earl of Rosse, who was the first to recognize the spiral nature of this “nebula” in 1845. Image: William Parsons, Observations on the Nebulae, Philosophical Transactions of the Royal Society, 140, 499-514 (1850) M51’s smaller companion galaxy, NGC 5195, is also visible, but the bridge connecting the two can only be detected in larger instruments.įirst sketch of a spiral “nebula” (i.e., galaxy), as published in 1850 by Lord Rosse. The galaxy’s bright core appears more defined in 8-inch instruments, which also reveal the galaxy’s large halo and a hint of the dark dust lanes and spiral arms. Messier 51 appears as a patch of light in 10×50 binoculars, while small telescopes show a more diffuse patch of light with a bright central region. M51 is also the brightest example of an interacting spiral galaxy in the sky. ![]() It is quite bright and appears face-on, which makes it a popular target among amateur astronomers and astrophotographers. In good conditions, the Whirlpool Galaxy can be seen in binoculars. The galaxy is positioned only 3.5 degrees southwest of Alkaid, Eta Ursae Majoris, the star that marks the end of the Dipper’s handle, or the tip of the Great Bear‘s tail.Īn imaginary line drawn from Alkaid in the direction of Cor Caroli, the brightest star in Canes Venatici, leads directly to M51. ![]() ![]() Messier 51 is one of the easiest Messier objects to find, as it lies in the vicinity of the Big Dipper asterism. It has the designation NGC 5194 in the New General Catalogue. The Whirlpool Galaxy has an apparent magnitude of 8.4 and lies at an approximate distance of 23 million light years from Earth. Messier 51 (M51), better known as the Whirlpool Galaxy, is a famous grand-design spiral galaxy located in the constellation Canes Venatici. ![]()
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