Messier 51, also known as NGC5194 and NGC5195, lies in the constellation Canes Venatici in the Northern Circumpolar Region. Its distance is estimated to be 23 million light-years from Earth. This pair of galaxies interacts with each other under the influence of gravity. The distinctive spiral structure resembles a snail with tentacles. In the long history of the vast universe, galaxies have pulled on, collided with, and merged with one another.