The Andromeda Galaxy (M31) is the closest large galaxy to the Milky Way
and is one of only ten galaxies that can be seen unaided from the Earth. In
approximately 4.5 billion years the Andromeda Galaxy and the Milky Way are
expected to collide. Andromeda is accompanied by at least 10 satellite
galaxies the most notable of which is the Triangulum Galaxy.

Galaxy Profile
Designation: M31, NGC 224
Type: Spiral
Distance from Milky Way: 2.5 million light-years
Diameter: 260,000 light-years
Mass: 400 billion solar masses
Number of Stars: 1 trillion

Facts About Andromeda
While Andromeda is the largest galaxy in the Local Cluster it is not
thought to be the most massive as the Milky May is thought to contain
more dark matter making it the most massive

The Andromeda Galaxy is approaching the Milky Way
at approximately 100 to 140 kilometres per second

The Andromeda Galaxy has a very crowded nucleus. Not only does it
have a massive star cluster right at its heart, but it also has at least one
supermassive black hole hidden at the core.

The spiral arms of the Andromeda Galaxy are being distorted
by gravitational interactions with two companion galaxies, M32 and
M110.

The Andromeda Galaxy has at least two spiral arms, plus a ring of
dust that may have come from the smaller galaxy M32. Astronomers
think that it may have interacted more closely with Andromeda several
hundred million years ago.

The Andromeda Galaxy is the most distant object you can spot with
the naked eye. You need a good spot away from bright lights in order
to see it.


images
First one is a picture of the great andromeda galaxy as taken by the hubble telescope

Second is a photograph of the andromeda galaxy taken by josh blash in the night sky