bright white light fading and relighting as it was heading toward groundI am a tractor trailer driver and was parked on the shoulder of the exit ramp for exit 88 on the I79 in PA. I park here m-f every week and take my 30 min DOT required break. It is a very dark area as there are no street lights and not many cars exiting at this time of day. I had gotten out of my truck and walked to the passenger side and was looking up at the stars which are very visible here, big and little dipper right above me, just as i was turning to get back into my truck I saw a very bright white roundish light off to my right which "came on" slowly to full brightness. I noticed then that it was moving downward toward the ground and as it did so it slowly dimmed to nothing and then slowly came back on to full brightness and then slowly dimmed to nothing and then came back on to full brightness again. It made no noise that I could hear. It was moving downward as if it were going to "land" or reach the ground and was "falling ot; not in a straight line but more of a meandering way...like a leaf falling from a tree. There also seemed to be a trail it was leaving and it seemed to be a bit hazy around the edges. There was a 10 - 15 ft. grassy incline at this exit ramp and I could not see it anymore when it dipped below the top of the grassy hill. It was too steep for me to climb so I do not know it "it" ever reached ground. I have no explanation for what it was. I was a jet engine mechanic in the air force in the 1980's and have seen all kind of aircraft. It had no standard aircraft lights on it...no red or green or strobe lights...it was just a very bright pure white light.