Triangulum Galaxy, California

The Triangulum Galaxy (Messier 33, NGC 598) is a prominent spiral galaxy in the constellation Triangulum and one of the closest large galaxies to the Milky Way, lying about 2.7 million light-years away. As the third-largest member of the Local Group after the Milky Way and Andromeda, M33 is notable for its loosely wound spiral arms rich in glowing hydrogen regions, including the enormous NGC 604, one of the largest star-forming complexes known in the Local Group. With a relatively small central bulge and widespread ongoing star formation, the Triangulum Galaxy offers a clear view of how spiral structure and stellar birth proceed in a less massive disk galaxy.