I think I've seen that program too. I also recall a program on Discovery about the Moon that eluded to its presence contributing to life on our planet (tides and deflecting incoming asteroids, if I remember right).
I see where you're going with this, but we'd see the effect in most galaxies right now.
Correct me if I'm wrong on this but at the center of most galaxies right now are black holes.
But currently no galaxy we know of is sitting perfectly still and neither is the black hole in it's center.
If...