We will never find out everything on earth. At least not in our lifetimes.

I've argued that science and math evolves the same everywhere (with some variance in time and discoveries). This includes social science. I believe in order for us to get to the point of long distance space travel we will have already evolved social science to the point where we embrace determinism. If this happens everywhere then all intelligent enough life would come to this conclusion and eventually be peaceful. Or destroy ourselves, whichever comes first.

Edit: my point being they'd all be peaceful but also recognize we aren't evolved so likely stay away from us.