According to scientists, at the rate space exploration is going, we'll probably make contact with aliens within 10 years. 

Despite the fact that Steven Hawking warns us that a more intelligent species would be likely to invade,  the biggest concern is that if we do find proof of alien life, it's going to cause people to question their religious beliefs.

In a universe where our galaxy is compared to a marble in an Olympic swimming pool compared to the known universe, I don't think we can discount the possibility of other life out there.

I don't think the discovery of alien life would cause me to question my core religious beliefs.  That said, I'm with Hawking... If there's life out there, do we really want to send greeting cards?