It is interesting that long before the collision, the, Andromeda galaxy will get easier and easier to see with the naked eye. That is going to be incredible.
I wonder what the distance will be before it becomes as visible as our moon in terms of how much real estate it takes up in the sky. Seems there will be a nice viewing distance before it get so close our entire sky is changed ...wonder what the early part of the collision will look like to observers here on earth.
The galaxies are moving towards each other at around 402,000 kilometers per hour, and it will take around 4 billion years for the collision. Upon collision our sun will have expanded but not yet be a red giant. Source
RE: Beautiful Corner of the Universe - The Andromeda Galaxy