Mike Wall has his doubts:
The Bible, Koran and other sacred texts of the world's major religions stress God's special concern for humanity and for Earth. So the discovery of aliens — microbes on Mars, say, or signals from an intelligent civilization in another solar system — might seem threatening, by implying that we and our planet aren't all that special. But our species has had plenty of time to get used to this idea. Nicolaus Copernicus made perhaps the first powerful case for it in 1543, when his seminal work "On the Revolutions of the Celestial Spheres" showed that Earth revolves around the sun, rather than the other way around.
George Dvorsky nods:
Darwin's idea was particularly devastating to religions, because it offered a complete explanation for the origin of life. God is completely unnecessary for evolution to work -– that's what makes it such a powerful idea. Yet, over 150 years later, religions are still flourishing, a sign that it's going to take a lot more than a monumental discovery to quash religious sentiment.