We are pretty much at the mercy of whatever alien species finds us first. Better hope they're friendly or we're fucked. It won't be like movies, we'll be extinguished in an instant. Or much worse, used as food, energy sources, slaves, god knows what else. Aliens are always thought of in a human way, the reality could be much different. Invisible gas monsters that absorb water in all forms(we're around 90% water).