any example? what cause two galaxies to collide? a galaxy contains stars, does it mean stars and stars, planets and planets will collide?
https://en.wikipedia.org/wiki/NGC_6052 The distances between stars compared to their sizes is so large that collision between stars would be extremely rare. For a comparison, imagine two swarms of bees meeting, with the typical distances between individual bees in each swarm being so large as to be measured in 10's of kilometers.
It means that the stars and the planets in the galaxies may collide. But most likely it will look like an occasional meteor, just as we see now. Most of the objects will miss each other and end up in each others orbit, but some will collide.
Yep. We're about four lightyears from our nearest neighbor star. Almost enough room for a Russian to avoid a collision.