I consider myself to be a Christian and yet I can accept the possibility that there might be other planets with intelligent life. I can even accept the fact that this intelligent life has managed to travel through space and is here now observing us.
My God is not limited to just one planet in the Universe. His glory is infinite.
Statistically and scientifically speaking, alien life almost certainly exists. What does it mean for Christianity if we truly are not alone in the universe?
www.beliefnet.com
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There is nothing wrong with believing that humanity is not alone in the universe. The Bible, after all, makes it clear that God created everything in the universe. That would include any form of alien life, and the Bible never explicitly says that humans are the lone lifeforms in the universe. That said, belief in aliens does raise a number of questions for Christians. The first and largest, of course, is how aliens fit into Christians ideas about salvation. Did Jesus’ death save every living being, or did it only affect humanity? If it was the latter, does that mean that human Christians have a duty to evangelize aliens, or did God incarnate repeatedly across various inhabited worlds in order to save all of His creations? The belief systems of the extraterrestrials might be able to answer that question. After all, their religion may turn out to closely mirror Christianity.