Triangulum Galaxy
The Triangulum Galaxy is a spiral galaxy
Spiral galaxy
A spiral galaxy is a certain kind of galaxy originally described by Edwin Hubble in his 1936 work The Realm of the Nebulae and, as such, forms part of the Hubble sequence. Spiral galaxies consist of a flat, rotating disk containing stars, gas and dust, and a central concentration of stars known as...

 approximately 3 million light years (ly) from Earth in the constellation
In modern astronomy, a constellation is an internationally defined area of the celestial sphere. These areas are grouped around asterisms, patterns formed by prominent stars within apparent proximity to one another on Earth's night sky....

Triangulum is a small constellation in the northern sky. Its name is Latin for triangle, and it should not be confused with Triangulum Australe in the southern sky. Its name derives from its three brightest stars, of third and fourth magnitude, which form a nearly isosceles long and narrow triangle...

. It is catalogued as Messier
Messier object
The Messier objects are a set of astronomical objects first listed by French astronomer Charles Messier in 1771. The original motivation of the catalogue was that Messier was a comet hunter, and was frustrated by objects which resembled but were not comets...

or NGC
New General Catalogue
The New General Catalogue of Nebulae and Clusters of Stars is a well-known catalogue of deep sky objects in astronomy. It contains 7,840 objects, known as the NGC objects...

, and is sometimes informally referred to as the Pinwheel Galaxy, a nickname it shares with Messier 101. The Triangulum Galaxy is the third-largest member of the Local Group
Local Group
The Local Group is the group of galaxies that includes Earth's galaxy, the Milky Way. The group comprises more than 30 galaxies , with its gravitational center located somewhere between the Milky Way and the Andromeda Galaxy...

 of galaxies, which includes the Milky Way Galaxy, the Andromeda Galaxy
Andromeda Galaxy
The Andromeda Galaxy is a spiral galaxy approximately 2.5 million light-years from Earth in the constellation Andromeda. It is also known as Messier 31, M31, or NGC 224, and is often referred to as the Great Andromeda Nebula in older texts. Andromeda is the nearest spiral galaxy to the...

 and about 30 other smaller galaxies.