If the earth was flung out of the solar system by something elses gravity, then it's likely the rest of the solar system, or the majority of it, would be destroyed as well. My biggest fear is a black hole coming close to earth, because there likely won't be anything we could do about.

Still 10s or 100s of light years apart, things would definitely be more interesting in the center of the galaxies as they merge but not by much.