The Vatican have announced they are comfortable with the idea of alien life. The good news for aliens is that they may be free of original sin. The bad news for aliens is:
…extraterrestrials would benefit equally from the “incarnation”, in which Jesus Christ, the Son of God, assumed earthlings’ flesh, body and soul in order to redeem them, which Funes called “a unique event that cannot be repeated”.
Indeed. The ucky aliens face prostelyzation when they come earth.
Aliens: We come in peace and bring the secret of interstellar travel!
Humans: Have you heard about your Lord and saviour, Jesus Christ!
Aliens: Errr…we must be going. (to each other as they leave) Kang, you told us that there was advanced life on this planet.
Many moons ago I did read a short story (I remember the author as being Phillip K Dick but I could be wrong) on what happened when human religion encountered an alien religion. The aliens were quite aghast at the idea that adherents to a religion would eat the flesh and drink the blood of their god. They felt the opposite was a more ideal realization of god.
Which makes the point that aliens may not be devoid of religion and if they do have some concept of god, it would likely be very different to our own.
Godless or not, intelligent alien life would be a thorny issues for most major religions.