Unknown object in sky, over Sterling VA in the early 1980s

I will never forget this night, simply because I was so young and it scared the daylights out of me. It was as any other child night was for me. I had been in bed for some time, asleep for what I remember to be a few hours. To this day, as I think about it, I can not tell you why I woke up. But then again, why do kids normally wake up in the middle of the night? I was around ten years old. It was a summer night.
 Anyhow, I woke up and there the lacy curtains I had in my room, I twisted in my bed to look out the window. I had thought I heard something. I just remember looking out the window and looking up the steep hill in the backyard. The night sky was blue-blue. But lit enough with the stars and other lighting around that you could see the sky and stars.
 I seen this object. It was huge. Round, like pie shaped from the angle I was looking up to it. It was at least three- four stories tall. There were a few white lights in various places on the craft, but what I will never ever forget.. Was that even at my age, I knew no airplanes just stayed in one spot in the air like this did.
  I was terrified at that young age. This thing had lights that ran around and around the thing, from right to left. Three colors, red, blue and green. Constantly. I remembered looking at it for what at the time seemed like forever. But now, it surely, couldn't been more than a minute or two. I ran from my room moments later, to my parents room. I tried waking up my parents. They wouldn't listen or believe me. Now, the other bit of news that sticks to me? I didn't remember hearing noise, or maybe I didn't think there was any noise while in my own bedroom. However, when in my parents room, I heard this hum. It wasn't one of them ear splitting, deaf defying hums or anything like that. It was soft. My parents later did calm me down enough so that I could sleep, but it was with them that night.
 You don't forget things or make this kind of stuff up at the age I was. I was around ten. And now, I'm 39 and its like it was yesterday. I will never forget this.
Witness indicates that the date is approximate.  PD