Very large soundless aircraft.On the second night of the recent meteor shower, myself, my wife and son and daughter were sitting on the tailgate of my blazer watching for meteors. We were looking to the general west and southwest areas. Suddnely, I spotted an aircraft to the west of San Manuel (where we live). I said to my wife and kids, "Look at the size of that airplane". It was very large and seemed to be a triangle shape. I realized it was moving much to slow to be an airplane. The night sky is very clear here and I could see the size of it by how much of the stars it was blocking out as it moved southward. It was in my estimate the width of about 3 football fields and had 3 very bright lights that were white. One light was on each corner of the craft. It appeared to be of a triangualr shape. My son asked me why we couldn't hear it and I realized that as close as it was, we should have been able to hear it. There was no sound. Very rarely do we see aircraft in the sky over San Manuel and when we do, they are at a very high altitude. This craft was at approx. 5000 feet and about 1 mile to the west of where we were sitting. Suddenly, the craft turned to the west and either disappeared or turned off its lights.