FAST low flying silent triangleMe and my girlfriend were out to watch the meteor shower, and had just turned off the yard light. We were both staring into the sky and simultaneously we both pointed and asked each other "what's that". We could see a large low flying triangular shap zooming across the sky heading directly south. I can't say how fast but I have never seen a plane fly that fast in my life and it was totally dead silent. At its closest point over us you could make out 5 very dim lights, or reflections from another light across the yard. The lights were all white it had one on each "wing" tip one on the point and one halfway between the tips and point on each side.We were looking north east as the meteor shower was supposed to be concentrated in that area, we first spotted the triangle coming over our bins approximately 100 yards directly in front of us. And it vanished above our house to our right seconds later.I am thinking it may be military as we have had Apache helicopters fly low over our farm in day time and people have seen stealth bombers during the day but at very high altitudes. We are almost directly North of a big United States military base on the other side of the sweet grass hills in Montana.I am interested to know how common a sighting like this is around my area, if you guys don't mind thanks