I do not know what I was expecting, but I suppose it is relieving to know there are only two unexplained sounds on the list. I wonder if it is a coincidence th

I do not know what I was expecting, but I suppose it is relieving to know there are only two unexplained sounds on the list. I wonder if it is a coincidence they were all detected in the 1990s or if that is because of some sort of declassification time elapsed.