I was walking my dog near my home as I always do at the same time every evening.The area is a park in front of my house. It was snowing with no wind and it was a full moon so it was quite bright with the reflection Of moonlight off the snow.Snow was falling straight down to the ground. I was on why way back to my home when I heard a roaring sound coming from my left side(north side) I looked but could see nothing.I heard it go over my head but could still see nothing until it passed to my right side. At that moment I saw a translucent boomerang shape with about a three meter wing span flying directly south towards a large fir tree. It was about two meters above my head and I only noticed it because of the trail of snow going over the objects sharp angled wings. I am certain the object was invisible apart from this.I was in a state of shock. I took the dog home and went back because I was sure it must have hit the fir tree. But could find nothing. I told my wife and a few friends about it but most mostly laughed at so I haven't really spoken to anybody about it since for fear of being ridiculed.It's been a few years since the sighting and I can't remember the exact year and month.