disk shape object with beam

It was about 10-10:30 p.m. when a friend, her boyfriend at the time, my kid sister, and myself were out at the creek.  There was a pulloff where you park your car and then you walk to the creek, I say we were about there a half hr before we had noticed in the distance(about 2 miles away from us) something was rising straight up from the ground. Underneath the obgject was white beam that shone as it was raising verticle up from the ground.  It was  at a slow pace and as soon as it got about 20 feet into the air it stopped in mid air and hovered in place with the beam still on for about 45 seconds and then it turned off its beam and started to come toward us.  As it passed over us it was only about 10-15 feet above us.  As it was paasing above us it turned a set of lights that was around the edges.  On the edges it had lights. They would go in sequence and flash red, blue, green.  While it was passing us it had a low humming sound. It passed slowly by and then! it shot off and was gone.  I think that was the most amazing expierence that I have had happent to me.  I remember that when it was gone all 4 of us looked at each other and all said basically the same thing.  "If we told anyone they probably think we were full of it" .  I know what I saw and nothing will ever make think it was a aircraft of our world.
Witness indicates that date is approximate.  PD