Is This Why We Haven’t Found Alien Civilizations? - STELLAR

Looking up at the stars makes you wonder: what and who is out there? And why haven’t we seen any other intelligent civilizations given the vast size and age of the universe? They’re complicated questions and although we haven’t met any other space-faring species we do have a way of calculating just how many alien civilizations might be out there as well as some rather frightening ideas as to why we might not have met them.