The Andromeda Galaxy is a massive spiral galaxy visible to the naked eye from dark sky locations. It is the largest galaxy in the Local Group, which also includes the Milky Way and about 30 smaller galaxies. Andromeda is on a collision course with our galaxy, expected to merge in about 4.5 billion years. The galaxy contains an estimated one trillion stars, significantly more than the Milky Way’s 200-400 billion.
Names and Catalog numbers
– Andromeda Galaxy
– Messier 31 (M31)
– NGC 224
– UGC 454
Position and the cosmic neighborhood
The Andromeda Galaxy is easily visible in the northern sky, appearing as an elongated smudge to the naked eye. It is accompanied by two prominent satellite galaxies, M32 and M110, which can be seen through binoculars or small telescopes. The galaxy is part of the Local Group, a collection of galaxies that includes the Milky Way and several other smaller galaxies.
Nice to Know
1. The Andromeda Galaxy is the most distant object visible to the naked eye from Earth.
2. It contains about twice as many stars as the Milky Way.
3. The galaxy’s disk spans about 220,000 light-years, making it more than twice the size of the Milky Way.
4. Andromeda is one of the few galaxies that is blueshifted, meaning it is moving towards us rather than away.
Brightness, distance and size
The Andromeda Galaxy has an apparent magnitude of 3.4, making it visible to the naked eye under dark sky conditions. Located approximately 2.5 million light-years away, it spans about 220,000 light-years in diameter. In the night sky, the galaxy appears to cover an area of about 3 degrees by 1 degree, which is equivalent to six full moons by two full moons in apparent size.
