I was indoors watching television when I heard a sound. It was almost subsonic as I think I felt it more than I heard it. I am not sure I can find the words to describe the sound. I had heard this sound maybe 6-10 times since I've lived here, but have never seen anything to identify what it could have been. This particular evening I heard the sound, asked others in the house if they heard it, then went outside and looked up. Above my house was a large, maybe 20-30 feet across, glowing circle. It wasn't emitting light but seemed to be lit from within. After about 3 or 4 seconds it went straight up. I saw the light go from a large circle to a very small circle then disappear. I just stood there trying to figure it all out. I could not see the entire circle so I am assuming it was just a circle, because it was directly over my house and I could just see about 2/3 of it from where I was standing beside my house. I now want to know why? I have always been interested in sightings but never had one like this before. Now I think I am just more confused then before.