MobBoss
Off-Topic Overlord
That's Dark Energy, not Dark Matter; Dark Matter is what gives galaxies its shape and is very weak. Dark Energy is very weak, too; there's just a lot of it. And both are not forces, but rather matter/energy that interact with gravity. Gravity is pathetically weak.
You are correct, I meant dark energy. But if dark energy can possibly do this:
There are some very speculative ideas about the future of the universe. One suggests that phantom energy causes divergent expansion, which would imply that the effective force of dark energy continues growing until it dominates all other forces in the universe. Under this scenario, dark energy would ultimately tear apart all gravitationally bound structures, including galaxies and solar systems, and eventually overcome the electrical and nuclear forces to tear apart atoms themselves, ending the universe in a "Big Rip". On the other hand, dark energy might dissipate with time, or even become attractive. Such uncertainties leave open the possibility that gravity might yet rule the day and lead to a universe that contracts in on itself in a "Big Crunch".
Either way, being the force behind the 'big rip' or the 'big crunch' sounds pretty darn powerful to me.