M51, also known as the Whirlpool Galaxy, is a spiral galaxy located about 23 million light-years away in the constellation Canes Venatici. It is famous for its distinct spiral structure and is interacting with a smaller galaxy, NGC 5195, which gives it a unique appearance. M51 is one of the most studied galaxies due to its well-defined spiral arms and bright core. Discovered in 1773 by the astronomer Charles Messier, M51 is cataloged as Messier 51 in his famous list of nebulae and star clusters. It has a diameter of approximately 76,000 light-years and contains billions of stars, making it a significant object of interest for both amateur and professional astronomers.