Curiosity

I'll bet that I know what you're thinking right now:

You're thinking, "Geez, I have always wondered what would happen if our galaxy were to collide with another galaxy."

Well, wonder no more.  It's going to happen.  The Andromeda galaxy is on a collision course with the Milky Way.  And this collision ain't gonna have no creamy nougat filling.  These two galaxies are racing together at the mind-boggling speed of 500,000 km/hr.  That only gives us about 3 billion years to get ready for the most rocking-est roller coaster ride ever.  That may seem like a long time, but folks are starting to live longer these days, so your great to the nth power grandkids may be around to see it.  They'll be hairless, wing-ed, three-fingered waifs with the ability to disassemble their corporeal selves out of harm's way when the time comes, but they'll still ultimately have you to thank (indirectly) for their life.

Apparently, it'll take about a billion years for the collision to run its course and to have the heretofore separate galaxies form one 'elliptical' galaxy.  For a computer simulation of what the whole she-bang could look like, head over yonder.  Dancing on a cosmic scale.