According to ScienceDaily, the Milky Way spins faster than originally projected, to the tune of a hundred thousand miles faster than you might have learned in school. That means it's also heavier than the scientific community used to think.
Then, of course, there's this:
The larger mass, in turn, means a greater gravitational pull that increases the likelihood of collisions with the Andromeda galaxy or smaller nearby galaxies.
And who doesn't enjoy a good intergalactic collision?
Milky Way image credit: astronomy.org