" If evidence of extraterrestrial life appeared in our solar system, would we notice? If we are expecting the bang of gravity-defying ships on the horizon, do we risk missing the subtle sound of other arrivals? What if, for instance, that evidence was inert or defunct technology- the equivalent, perhaps, of a billion-year-old civilization's trash? "

― Avi Loeb , Extraterrestrial: The First Sign of Intelligent Life Beyond Earth