The silent object had three orange ball-shaped lights that seperated from eachother as it flew over the mountain.

Seven friends (male) and myself had walked down to the neighborhood lake one summer's evening. We were hanging out in an area that overlooked the lake. As we were sitting down on a ledge talking to each other, I noticed an object flying straight at about 60mph and 300ft in the air on the other side of the lake (about a quarter mile away). At first it looked like the lights of a plane, but as I kept my eyes on it I noticed that there were no blinking lights just three orange colored ball-shaped lights. At the time nobody else was paying attention to it because it sort of blended into distant street lights, but when I realized seconds later that there was no sound coming from it, I pointed it out to everyone saying "check out that plane, Its not making any sound." Everyone watched as the object flew another 30 seconds until it was over a mountain about a half mile away. All of a sudden as the object was over the mountain its three ball-shaped lights slowly seperated from eachother downwards onto the mountain. All of us were stunned as the balls disappeared behind the mountain and today fourteen years later, all of us are college educated professionals and yet we still refer to the event as the UFO.
Date of event is approximate.  Source describes self as having a responsible job in academia.  PD