Andromeda
Andromeda is the closest galaxy to our galaxy and is now heading straight towards us. In about 5 billion years The Milky Way and Andromeda will be one galaxy.
How It Formed Age
Andromeda was formed out of the collision of two smaller galaxies between 5 and 9 billion years ago. 9 billion years old
Seen From Earth?
Andromeda is able to be seen with the naked eye on nights with no moon, no clouds, and in an area with low light pollution.
Light Years Away
2.5 Million Light Years Away
The Deadly Collision
Andromeda's proximity will be deadly to our galaxy. The two galaxies are rushing closer to one another at about 70 miles per second (112 kilometers per second), but by that time the Sun will have swallowed up Earth and other planets around it. By this time our solar system will be nothing.
Discovered
Since Andromeda can be seen with the naked eye discovery was not necessary, but star charts and maps were found dating back to the 960's.
Andromeda seen from earth
Infrared picture of Andromeda