UFO Sighting in December 1978 in Seattle, WA.

I was 10 years old at the time I saw this.  It was early evening and I was looking out the window.  I saw some lights that started rising up and I said, "Oh my God, there's something out there!" and my sister and mother rushed to the window to see.  It was shaped like two pie plates inverted together with lights around the edge of various colors and a red light on the top.  It had openings that looked almost like small, round windows that were between the lights on the edge.  The surface was smooth and metallic looking.  It just hovered above the ground without a sound for a few minutes and then took off straight up into the sky in the blink of an eye.  I don't think it was more than 50 yards from the house; it was really close.
 The really strange thing about it is that all of us have different memories of what we saw.  I remember my brother and uncle being there but neither of them remember it or think they were there.  My mother remembers it going over the house and then hovering and my sister remembers being outside and watching it go over the house, hover and then take off in the sky.  It seems like it was still a little light when I first saw it, but when it just took off straight up, it was dark.
Date is approximate.  PD