That high frequency noise has been there for a while. I remember it being there at least during last fall term exam time. When I go it just fades into background noise eventually.I think it is a light. Sometimes my old lamp makes a high frequency noise when I turn it on, so maybe it is the same thing.
It's called the Wolfgang-Lutzfield effect. It's from not having enough crazy sex. There is only one known cure.
It wasn't there at the beginning of the term. I know this because I practically live there. In fact I'm there right now.
I'm not saying it's Aliens....But it's aliens