The Andromeda Galaxy (M31) is the closest large galaxy to the Milky Way and is one of a few galaxies that can be seen with nakes eyes from the Earth.
In approximately 4.5 billion years the Andromeda Galaxy and the Milky Way are expected to collide and the result will be a giant elliptical galaxy.
Andromeda is accompanied by 14 dwarf galaxies, including M32, M110, and possibly M33 (The Triangulum Galaxy). The Andromeda Galaxy lies between the Pegasus constellation and the point of Cassiopeia. It looks like a blur or a hazy oval in the sky.
Because it is such an easily observed feature in the night sky, it is impossible to say who discovered the Andromeda galaxy. However, Persian astronomer Abd al-rahman al-Sufi’s The Book of Fixed Stars from the year 964 contains the first known report it.
The Andromeda Galaxy has a very crowded double 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.
Designation: M31 or NGC 224
Diameter: 220,000 light years
Distance: 2.54 Million light years
Mass:1,230 billion M, Number of Stars: 1 trillion
Group: Local Group