The Whirlpool Galaxy – Messier 51
The Whirlpool Galaxy, also known as Messier 51a, M51a, or NGC 5194, is an interacting grand-design spiral galaxy with a Seyfert 2 active galactic nucleus in the constellation Canes Venatici (the Hunting Dogs). It was the first galaxy to be classified as a spiral galaxy. Recently it was estimated to be 23 ± 4 million light-years from our Milky Way galaxy.
Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)