If someday we create something that gives us immortality, that allows us to life forever somehow- by changing bodies when we get old or just staying forever young... If someday this happens, what will that do to God? Well, faith in him. If people will never die, they don't ever have to fear hell or judgement. If there's no diseases or STDs or anything of the sort, sexual sins will be rampant. However if you couldn't kill anyone, then there would be no more murder. Sins there may decline. Regardless, if we live forever, I believe that people will stop worshiping God. Immorality would destroy faith.
Now, if we discover aliens or they discover us, that would really hurt faith. And if these beings have a faith or don't, it will hurt our faith. All religions could be torn down from a first contact with another race.
There's all sorts of things like this I wonder how they'll effect world faith. It's an interesting thought process.