Silver disk with light beam

In  June of 1976 my husband and I were traveling to Dalewood on I-20 from Meridian, Ms. it was a clear summers evening just going into twilight when I noticed a bright light shining through a thick stand of pine trees to our left. I thought that "sure is a bright yard light". About that time we topped a hill on the interstate and directly over the trees we saw a large silver disk hovering right over the treetops. It was approx. 40-50 feet in diameter and encircled with different colored lights. Right from the center of the disk a VERY bright beam of light was directed into the trees. I had the feeling that it was collecting something or leaving something with the light beam. In just a few seconds the beam turned off and the disk rose about 30 feet in the air and departed at a fantastic rate of speed toward the horizon. Several cars slowed down to look also. We had our windows down and the object was soundless. My husband was terrified over the event. We listened to the radio and watched the papers for several days to see if there were any reports. But there weren't.