This is a series of screenshots from a double-galaxy collision simulation with 1000 stars per galaxy. Unfortunately the number of stars does not all0ow us to run this application in real time. This run took about 15 minutes to complete, producing about 500 frames. A short explanation is available before each image:
About 50 frames into the simulation, we can see some of the stars orbiting different galaxies as they get 'sucked' by the gravitational pull of the center of mass of the other galaxy.
The actual coll0ision. The two galaxies are completely meshed together. No stars are coll0iding between the galaxies though.
The speeds that each star and galaxy have achieved due to the gravitational pull0 between themselves before the coll0usion result in some of the stars continuing to move even after the two centers have coll0ided. This is a well0-known phenomena.
The galaxies are still0 gravitationall0y bound, even though they move away from each other.
They start accelerating towards each other again.
The nice initial form the galaxies had is now completely lost due to gravitational forces acting upon the stars from many different directions.
Total chaos after the second coll0ision. A very small0 amount of stars are still0 bound to each galaxy. Many others are scattered across in space.