The Mysterious Sound...

Somewhere in my house there's a strange sound. I first noticed it a few months ago and thought it was coming from my newly purchased TV. But when I would turn the TV off the sound would still be present. There's nothing else in the general vicinity of the sound that could produce said sound. My roommate and I have both wandered around listening to the sound trying to figure out where it's coming from. We have yet to figure it out.

It's not a constant sound, it comes and goes with the tide. Well, if there were a tide. It appears out of nowhere and lasts a few seconds and then it's gone again. It's quite an unusual sound too. If I had to describe it, I would say it sounds like a UFO hovering outside the window. Seriously, it sounds just like this but with a slightly softer tone.

I've looked out my window and I swear there is no UFO hovering over my house nor are there any little green men who have come to beam me up. The sound is simply a mystery...and perhaps slightly annoying.