Is there intelligent life on other planets? Probably. It seems likely that somewhere out in some other solar system there are planets which can sustain life. Why don't they get in touch with us? Either they aren't as advanced as we are and aren't yet capable of radio transmission, or they surpassed our level of intelligence long ago and self-destructed just as we're going to do.
I suppose it's possible some life forms managed to build a spaceship before their planet was destroyed, but if that's the case one would assume they're on a mission scouring the universe for the materials they need. If they find Earth, they'll have to wipe out the human population as quickly as possible in order to preserve what's left. There's nothing untainted on our planet so they better hurry. In fact, maybe those aliens have already passed by Earth, assessed the state of our resources, and determined everything was too defiled to use. Lucky us.