Large glowing green in color looking up at the bottom it was round

My friend and I were walking home after a basketball game when a large bright green object went over our heads. It was about 1000 feet in the air. We estimated it's size to be about the size of a football field,it was close enough that we could see the edge of it and could tell it was a solid object. There wer trees on both sides of the road so we couldn't see it for very long but I would say it was moving about twice as fast as a fighter jet. It didn't make any sound. There was alot of reports about cattle mutilations around that time.We were only sixth graders at the time we saw it,it scared us so bad that we ran about a mile home without stopping. I have wondered about this all my life, so I decided to report it.