Funny thing about two galaxies colliding. They never collide. The space between all the stars and planets is so vast that they literally phase between each other, more or less unharmed. Although, in rare cases, the "Super Blackhole" in the center (Cont)
Treehodger - February 18, 2010, 1:33 am,
Can actually collide with the other Super Blackhole. In this rare instance, the two galaxies can be pulled into each other, creating this... http://farm4.static.flickr.com/3363/3234499700_efa87d02e4_o.jpg
MasterMachine - June 15, 2010, 6:24 am,
Just to add to that, the stars will probably never collide, but the black holes WILL. Thats garenteed, they to much gravatational pull on each other to NOT collide. Also, the Andromeda Galaxy (the one nearest us) is planning a head on collision with us.