I think this is a topic that we have all thought about at one point. If you think of a little green guy when you hear about aliens this only means that Hollywood has done its job at making you think a certain way. The idea of the little green guy will keep one chasing a hopeless dream. Have you ever stopped and asked yourself what an alien is supposed to look like? Wouldn't it just be something else that is alive that isn't human?
So if I understand this correctly, my cat is an alien?
No Thatcher! Your cat is not an alien because it is a cat!
So what about my puppy? Is she an alien?
No you dingleberry! That is a dog!
So at what point do we locate something that is living, non-human, or anything we have previously named, and decide yep, that is an Alien?!