Comment Re:Uh... I have a bad feeling about this. (Score 2) 25
F = G * (m1 * m2) / r^2
Or as we call it, Newton's inverse square law, where the force of gravity on any two objects is inversely proportional to the square of the distance between them. Space is really really really really really big (the observable universe has a diameter of about 93 billion light-years), so it is literally impossible for any combination of mergers to have any effect beyond an infinitesimal region of the universe. Even a galactic merger which caused two supermassive blackholes to merge would have little or no measurable effect on a neighbouring galaxy as far away as Andromeda is from us (about 2.54 million light years away).
In fact, it's not until LIGO that we have even been able to detect the mergers of super dense and super massive objects like neutron stars and black holes, just to give you an idea of how the inverse square law limits the influences of gravity over very large distances.