This from a list I frequent:
"Resonant amplification is a powerful thing. For example, did you know that "ghost" sightings are generally an effect of the eye's resonance being a harmonic of half the resonant wavelength of one of the dimensions of the room the witness is in (typically 19 hz)? The resonance causes the fluid in the eye to refract light unevenly creating a gray patch which the mind then fills with its own imagination. This effect can be triggered by extremely low levels of infrasound, particularly when the wavelength of a chimney cavity is resonant to the dimensions of the room, a breeze supplies the needed energy."I've been interested in the increased frequency of my own sightings, of cats especially, now that I'm in strange surroundings and tend even more to make recognizable patterns from the shaded chaos of a thousand things in my new apartment not yet put away. The movement of a large floater (in my eye) in a poorly lighted room can induce "cat" instantly, even when and regardless of the fact that I "know" better. The part of my mind that recognizes things is necessarily free of higher functioning filters, and because I'm much more curious than bothered by such apparitions I'm in no rush to suppress their memory. Happily, there's no accounting for the patterns one's brain comes up with.
I have yet to experience one of the "resonant amplification" sightings noted at the top. But it seems perfectly possible and reminded me of a recent lecture on antennae lengths.
Well, maybe one sighting some 50 years ago, in my first apartment: a long, narrow attic room. But that turned out to be mold under the wallpaper, I think, unless it wasn't. Then as now I'm more interested in my own experience in the face of my firm convictions that they ain't no sich thangs. I was less sure then than now, and half-accepted the possibility of powers, gods, and ghosts unknown. It was a great time to be a science fiction/fantasy fan.
Being so near several small lakes and parks, I occasionally get a line of ducks flying at head-height down the street outside my bedroom. Late last night one such group began honking just as they passed my window and startled me from a sound sleep so that I sprang up in bed, ready to defend against whomever was using that longsword so cruelly against helpless flesh, making it cry out so loudly and in such pain. Had that image sustained for another second I would have been searching about for my own blade, ready to run naked into the fray, fighting for the right and the good.
I don't have a sword, and that's probably a good thing. In dreams I've often carried and even used one, and on waking for a moment I sometimes think I really have one, somewhere.
Such moments make passage between worlds and timelines seem almost possible. I find those thoughts, frightening, dangerous, and delightful!