our sun is a third generation star, that means that another civilization had approximately 15 billion years minimum to develop to our point. We have been on the earth for, what, not even a million years?
There is a great probability that there are more advanced peoples wandering about space. Who knows what they look like or act like. For all we know, there are little men inside of protons and neutrons and electrons that are actually aliens from a distant galaxy who can travel on photons.