Every story I know about aliens coming to Earth has one of two basic plots: they’re bad guys who want to invade and kill/enslave us, or they’re good guys who want to explore Earth/enlighten us. Couldn’t this paradigm be expanded a bit?
Here’s a little idea I had for a story: an alien race—advanced, peaceful, and already rich in Earth’s natural resources, like water and oxygen—starts colonizing and mining another planet in our solar system for substances that they need, and which we neither have in abundance nor need, say Venus, for sulfuric acid, or liquid hydrogen on Saturn, or some other element of which we’re currently unaware.
Who would contact whom first? Would the new race say, “Hello! We’re moving in to Mars, which we see you’re not using, and just wanted to introduce ourselves. We’ll stay out of your way.”
Or would we notice them at work over there, freak out, and then later start wondering why they’re not doing anything to us? Might we send a message like, “Why aren’t you contacting with us?” And they might reply, “Why would we?”