What would happen if milky way Galaxy collide with nearby Andromeda galaxy ??

 This is not a part of Sci-fi movie  !!!

The galaxies Milky way and Andromeda are on a collision course .....

Right now, they are moving toward each other at about 110 km per second  !!!

We can heave a sigh of relief !!!

Because both the galaxies start making contact with each other in 4 - 5 billion years .....

Here is what actually happens ......

1.   CRASHING WON'T LOOK LIKE CAR CRASHING   !!!!

                      Both galaxies are 99.9% empty space .   Stars are tiny compared to the distance between them.

                       So when they collide, stars almost never hit each other !!!

                      Its more like two swarms of bees passing through each other.

2.  The real action is gravitational. As the galaxies merge, their gravitational fields tug on stars, gas and dust.

       Orbits get stretched and thrown out of whack. Stars become " rogue stars  " !!!

3.  Gas clouds do collide. This compresses the gas causing massive bursts of star formation.. This phase is called  "  Star burst  "  !!!

4.   Right now both the galaxies are spiral. But after the merger, new galaxy would be elliptical in shape.

5.  Both the galaxies have supermassive black holes at the center. They will eventually merge sending out gravitational waves.

6.  Probably nothing dramatic happens to Earth.  Sun is not going to get ejected or swallowed.  It will just end up orbiting in a new path of galaxy !!!