Silent black triangle over Louisville KYAt approximately 9:00pm we saw a red light in the sky moving from the northeast to the southwest. When it first appeared it was low in the horizon at around 10,000 feet in altitude. The light on the aircraft went out and we could see a triangular aircraft that was totally black with no running lights. It was totally silent and moved out of our sight into the horizon. This area is near the Louisville International Airport and seeing aircraft at all hours of the day is common, however this was very different because it flew across the normal flight path with no lights and no sound.