Interesting. @originate I'm not sure if you can answer this or not but when this happens (two galaxies collide) does it create a sort of chaos within the galaxies? Like do planets and stars collide and would inhabited planets recognize that this is happening to them? So for instance, if earths galaxy collided with another would we experience anything different or does it happen at such a large scale that the event goes mostly unnoticed?

These might be tough questions but if you have the answer, I'm very interested.