Are we alone in the universe? Top NASA scientists say the answer is almost certainly “no.” "I believe we are going to have strong indications of life beyond Earth in the next decade and definitive evidence in the next 10 to 20 years," Ellen Stofan, chief scientist for NASA, said at a public panel Tuesday in Washington. Full Story: http://www.latimes.com/science/sciencenow/la-sci-sn-nasa-search-alien-life-20150407-story.html
I think it's less a question of when we find alien life and more a question of when they find us! It will either be the start of a new age of peace and enlightenment for mankind, or the end of life as we know it. I think that after getting to know us, they'll be leaning towards the latter.
I think that if they wanted to 'destroy' us, they would have done it already. At least I hope so. (*Thinks about great flood, dinosaurs.)