The Vatican has know given the all-clear for Catholics to believe in life beyond our planet. The Rev. Jose Gabriel Funes, Jesuit Director of the Vatican Observatory stated in an interview that our universe is too big to rule out "additional forms of life even, intelligent ones." In an interview called "The Extraterrestrial Is My Brother" published in the Vatican newspaper (L'Osservatore Romano) Funes explained that ruling out the existence of aliens would be like "putting limits" on God's creative freedom. He also assured doubters that it doesn't contradict with their faith as Aliens could be among God's creatures.

Source: io9