Is there anybody out there? Maybe. Maybe not. Though there are more reason to believe that we aren't alone, nobody yet contacted us. Scientists are trying to contact them. Apart from UFOs stories we kept hearing and which scientists kept rejecting, something happened in 1977 which scientists are still baffled about. Amidst the persistent noises of this vast universe, scientists were able to hear a 'song' which lasted some 72seconds. The 'song' was too good to be an accident. Much to the disappointment of scientists, the song was never to be heard again. 37 years have passed since then but those 72 seconds never came again. Check this link for wonderful presentation by Brian Cox. In case, the song we listened to was some kind of accident, we, too, have sent our own messages to contact aliens. The earliest message was put on Pioneer 10 spacecraft in the form of a plaque. (See image below.)
                   Also see: Arecibo Mesasge