Triangular boomerang shape, dark gray/shadowy color, low altitude, silent,I was standing on the back porch as I often do, facing north, waiting for the dog to finish his business for the evening. It was just after 9pm. As I stood there, I looked up into the night sky as I often do, admiring the stars. It was a clear sky, and off to the far north-northeast, something caught my eye. It looked like a distant shooting star, but that soon became unlikely to me, as it was moving horizontally in what seemed then to be from north to south, and it did not burn up and disappear as would be expected. About two to three seconds elapsed, and I found my eyes focusing in on a silent, shadowy, blur approaching my location overhead. It was in the shape of what resembled a boomerang, about the size of a hang glider, or even slightly smaller. I was surprised to realize that it was actually at a very low altitude. I felt myself grasping to identify it, and trying hard to decide that it was simply a flock of travelling birds. I believe that what I was trying to call birds were actually 5 or 7 small, dull white lights, and as the object came nearly directly overhead, I could easily see that these lights were on the V-shaped outer edge of a dark gray colored craft. In fact, the craft appeared to be made of a similar material to a B-1 stealth bomber, although it definitely was not a B-1. It was traveling north-northeast to south-southwest, at perhaps 75 feet above the treetops. The craft was moving too quickly for a flock of birds, and yet considerably slower than what would ordinarily be the stall speed of an aircraft, perhaps 45-50 mph. Again, the object was completely silent as it passed nearly directly overhead, very stable and steady in course, at an altitude which I later realized would have been below normal radar detection. My experience was of an object that was only perhaps 8 feet across at best, and this was most puzzling of all. I would not say it was large enough to carry people. I live in a suburban area, and watched it disappear over the neighbors' treetops soon after passing over my! head. T he lights may have changed color, but I am not certain of this.Curiously, I've only had one other UFO sighting in my life, when I was an older child laying in the yard looking up at the stars, maybe fifteen or twenty years ago. That object was almost exactly the same as the one I saw recently, and I finally feel vindicated that the sighting I had then was indeed not a flock of birds.