very close encounter

I was only around 5 years old when this happened.  My older brother and I were playing in the backyard.  It was dark outside and it must have been close to time for us to go in.  I remember seeing this this flying just over the trees, maybe 30 ft from the ground and directly over our heads.  I didnt see the top of it, cause it was right over my head, but I did see that it was circular from the bottm, so I assume it was a disk.  On the bottom of this craft, was 4 large domes.  The domes were glowing a milky white color.  The craft was about 25 ft. in diameter and the only saound this thing made, was a humming noise, like bass on a stereo.  My brother was screaming"go away,go away"!!!  I felt differently about it, I remember feeling playful and was a yelling" come down, come down"!!!  The craft continued moving very slowly over the house and out of view.  
It's been a very long time since this happened, but it will stay in my mind for the rest of my life.
Witness indicates that date of sighting is approximate.  PD