Green circular light flying down the river, but it was dead silent and un-explained.I was with a 2 friends down by the waterfront, in the darkness, when all of a sudden this bright green circle came flying down the river, going about 2 times faster then a speed boat. It was a silent and calm night, but the green circle, didnt make one sound. It would of been approximatley 70 meters away.Then, another orange cirlce came down the river, but it only put it's light on every minute or so, and everytime it put its light on, it would be further down the river.It wasent a jet ski, a boat or any water craft because it was dead silent, and it was going way too fast.1 of the friends' i was with also said he was with his friend ( who is a pilot), just the night before, and he was on top of the hill, when a circular green/orange thing, was just hovering over the beach.My friend has a short video on his phone, but it dosent turn up because its too dark.I was wondering if there is any chance of knowing what it was.