Ignoring, for a second, all of the responses about Native American rock art and demons.
There are a few different schools of thought on how common life is in the Universe, how frequently intelligence evolves, and how often intelligence survives for long enough to allow a species to even reach out to its neighbors through radio or any other sort of signal. On the one hand, you have the idea that life is totally unique, which is very unlikely. Not impossible, but unlikely. On the other, you have the idea that there are extremely advanced civilizations all over the place, which invites skepticism since...well, we haven't found any yet.
Between those two, you have a lot of more probable views. Maybe life is rarer than it would seem, because of some factor that we don't know about yet. Maybe it's fairly common for life to develop, but not for human-level intelligence to evolve (which is what I lean more heavily toward), and the civilizations that do exist are too few and far between to discover each other except serendipitously. After intelligence develops, maybe it's rare for it to really go anywhere, remaining at subsistence or near subsistence levels for the course of its entire existence.
Or, maybe it's common for intelligence to evolve, and then run itself right off of a bridge. Not a particularly optimistic standpoint, since we're driving about two hundred miles per hour right now over the metaphorical causeway.
It's impossible to be sure, without any evidence, which of those ideas is correct. What seems unlikely, though, is that there are a lot of extraterrestrial societies out there who are capable of practical interstellar travel and that we're going to accidentally contact them and have them show up to rain fire on our planet. It's a fun plot point in science fiction, but there's a good chance that it's not possible at all, and if it is then it seems likely that it's extremely rare for a society to reach the point of being able to do that. We'd know by now if we were absolutely surrounded by extraterrestrials with the ability and desire to colonize every planet within reach. Either we'd see evidence of their existence in the form of megastructures like Dyson Spheres, or we'd fail to see evidence because we would be dead. One of the two, probably the latter.
Most likely, we won't know one way or another whether we're alone in our fairly close neighborhood for a very long time. Sending out signals probably won't get a response in the near future, but it's also probably harmless.