... the strange noise is back. We first head it back in January 2012 on a number of separate occasions and always at night. Last night it was back. Same exact sound only much much louder. This video was taken about half an hour after it first started, between 10pm and 10:30pm (it started at about 9:30pm-ish). A few friends from the area heard it too. It was pitch black, hence only the street lamp dots are visible in the video. No clue what it could be, but it sounds like a drone or large vac - the type used to clean heating vents. We didn't hear it over the spring/summer, but now that it's getting cold and fall/winter is here, it's back. That being said, we had massive aurora borealis activity that same evening and the night before, so it could be related. Who knows!