Overall, we find that, in the most limited case, which we describe as the Strong Copernican Astrobiological limit, that there should be a minimum of 36(−32+175) communicating civilizations in the Galaxy today, assuming the average life span of these civilizations is 100 yr. The nearest of these would be at a maximum distance given by 17,000(−10,000+33,600) lt-yr, making communication or even detection of these systems nearly impossible with present technology.