"There's solid proof against alien visitors (the ol' speed of light limitation bugaboo)."
And pre Einstein, that wasn't even known. So are your really so sure that - say 500 hundred years from now - that knowledge won't be overturned too? Even if it isn't, what about suspended animation, etc.
Consider this: Given our rate of advancement (and assuming we don't blow ourselves up by then), at some point might we not be able to seed another planet with life? If so - and given the countless numbers of galaxies, solar systems and planets out there - might someone else not have done the same thing to us already?
Is it the Christian belief that God will step in and specifically prevent us from doing that in our future?
Like I said before...this idea takes a LOT of "faith".
It is the Christian belief that God has given mankind dominion over the Earth (Genesis). It is also the Christian belief that with God, anything is possible (Jesus). IOW - God could intercede, but don't count on it.
I realize you asked about "Christian," rather than specifically "Catholic" teachings, but I'm answering in terms of Catholic because (1) with the Orthodox, the Catholics are the oldest historic Christian Church, and (2) unlike many Christian denominations, the Catholic Church has a body of explicit, written doctrines which are propounded on the basis of a permanent authority. They are quite definite. There's even a search engine so you can look up the most imporant doctrines at:
http://www.scborromeo.org/ccc.htm
T'aint like you need to get different people's opinions, or do any guessing about it.
No... he created the heaven and the earth....why would he stop us?
Even if we found "life" on other planets, that would still not explain away God.... or his creating us in his image or Jesus Christ.... it's nice to see that at least your curiosity is piqued.
I think some of the greatest Christian writers and theologians started as agnostics or atheist, looked at the question seriously and then logically came to the conclusion that there must be a "God"... and then under more observation and thought came to Christianity.
Good luck to you on your quest. I think we're all stumbling around and I do believe that we are given all the information and free will we need to make the right choice..