M51: Cosmic Whirlpool
This is the 51st entry in Charles Messier's catolog of two galaxies interacting in the south west. NGC 5194 might be the original spiral nebula, as seen here connecting with NGC 5195, its neighboring nebula. These are about 31 million light-years away in the constellation Canes Venatici. The sharpest image of M51 ever was taken with the Advanced Camera for Surveys on board the Hubble Space Telescope.
