Are we listening for little green men :)
We are Searching for extraterrestrial life in the universe. A grand scheme, but are we listening? We must think of how could a civilization possibly produce a signal powerful enough to be heard above the ever present background noise of our galaxy. Of course science fiction would have us believe in methods and frequencies well beyond our present capabilities and understanding.
As it is, our strongest radio signal would not be heard on a planet circling our nearest star. A growing space reaching civilization even a few dozen light years away would have the same problem. They might be there, but we would not hear them. All electromagnetic pulses are governed by the inverse square law. Basically, the signal gets exponentially weaker with distance.
So, is there ANY hope of us hearing from a civilization any real distance away –unless they violate all our known laws of physics and come visit us ? :)
well, the answer is no, but ……….
There is one way that an ultra advanced civilization could possibly communicate with all the universe despite the limitations of physics. Every thousand years or so a nova happens in a galaxy. It is quite conceivable that a really advanced civilization could find a way to “piggyback” or modulate signals onto the expanding wave front of the explosion. Even though a Nova is a brief event, they could use many frequencies at the same time…..
Everyone wants a form of immortality. This would give this great race a brief moment to announce to the entire universe “we were here; don’t forget us, even if all we knew is long dust by the time you see our star in briefly in the night”.
Who knows, theirs might even have been the star of Bethlehem……