I was walking north down my driveway to the trash bin around midnight and happened to look up in and saw a huge, pale green, almost translucent triangular shape. I was able to see it for a few seconds before it disappeared over the trees. It seemed to be possibly several hundred feet up under the overcast sky and was completely silent. There were no blinking lights but the object glowed as if lit from within. I estimate that its speed was over a hundred miles an hour and it appeared to be "gliding" in a straight line going northward. Seeing the object made me stop dead in my tracks and made me feel a little nervous. I went inside and described what I had seen to my father and then went back outside to look at the sky for a while longer but saw no other activity. There were no planes or helicopters in the sky when I saw the object or afterwards.