Human Beings Detecting Thermal IR?
Date: Thu, 6 Jun 2002|
From: William Beaty <>
To: vortex-l a eskimo dt com
You probably won't like this one, since it's entirely subjective (using
yourself as the instrument.) However, it's fairly amazing, at least it
was for me.
In good summer weather when there is a small thunderstorm nearby, look at
the dark black underside of the storm. Feel anything? Feel something
like a cold, "fresh" feeling inside your chest and in your sinuses? Now
look away, and that feeling totally vanishes. Look at various parts of
the sky, and that feeling is still gone. It's only there when looking at
the very dark blue-black part of the summer rainstorm.
I'd always noticed this effect, but put it down to illusion. I assumed
that, as I looked at the storm, it was giving me memories of cold rain,
(sort of like looking at bright red orange, and thinking of fire.)
HOWEVER, I recently noticed something really weird. While driving along
watching one of these storms through the open window (a really interesting
storm with rain shafts and green light deep in the darkest part), I turned
a corner... and the "feeling" totally vanished. Suddenly it was like
looking at a photograph of a storm. However, I was now watching the storm
through the windshield. I ducked my head out the open car window, and the
"feeling" came back full force.
What. the. heck!
OK, so now I looked at the storm, then ducked my head sideways so I was
viewing the storm through the windshield again. "Feeling" vanishes
utterly. Duck my head back and view it through the open window... and the
"feeling" switches on full blast.
Oh, and final tidbits: if I close my eyes or block my eyes with my hand,
the "feeling" also vanishes. Whatever this is, it is associated with my
eyes, that's why I put it down to purely a psychology effect.
But it seems to be entirely blocked by the car windshield. "Psychology"
isn't affected by a transparent object. What the heck is going on? It's
NOT like looking at the color red and imagining heat, since that's not
affected by a sheet of glass.
Aha! While writing this I just realized that windshields aren't glass.
They are two glass layers with polymer sheet sandwitched within. Does
this make a difference?
Damn, I wasn't thinking about this at the time. I could have tried
rolling up the side window and compared that with the "shielding effect"
of the windshield (the side windows are tempered glass, not the "safety
glass" polymer sandwich.) If there is a difference, then maybe it's the
plastic which is the shield, not the glass. (Shades of Russian Torsion
Has anyone here ever noticed this effect before?
Thur, 6 Jun 2002
I think I just confirmed this. While driving back from dropping off my
daughter, there was another one of those dark blue-black clouds nearby.
When I look at it, I get the "cold fresh" feeling. But when looking at
small clouds of similar color, I get nothing. When looking at trees and
Suppose that the "special" clouds are much colder than others? If so, and
if my eyes/face are sensitive to long IR, then windshield glass would
block the effect. Glass behaves as a hot radiator (hot at 70F or so.)
(Yes, the driver side window blocks the effect just as well as the
But WHY would these small dark clouds be cold? Maybe they contain
falling raindrops, but these should be no colder than the cloud droplets
within other clouds.
I was thinking these thoughts while driving, and the blue/black cloud was
now overhead. Guess what happened. I kid you not, IT STARTED HAILING.
As I'm typing this, half-inch hailstones are clattering on the roof and
shattering on the sidwalk outside my cellar window.
So, the weird "feeling" I get when aiming my eyes at certain clouds may
just be crude "IR vision." It takes large vertical winds and very low
temperatures to generate hail. I'm gussing that a thermal IR camera would
"see" a hail-bearing cloud as a big cold blotch against the relatively
If human beings have a thermal-IR sense, it seem to be associated with the
eyes. I'd guess that could just be corneal sensitivity to heat, and NOT
retinal sensitivity to IR. It hurts if you poke your cornea, so the
region is full of nerve endings. If the corneal nerve endings have
temperature sensors, they might act like a simple bolometer, and be able
to sense when a distant cold object is present.
It might be no more exotic than when you feel warm sunlight on your
skin. ...but somewhat more sensitive, and somewhat more directional.
But it DOES seem to be useful. I can look at various clouds and tell if
one of them is a storm with vertical winds and ice. I can see that such
a skill would come in handy, and probably be reinforced by evolution.
Ooops! There's some thunder! Cloud-electrification is associated with
strong vertical winds (updrafts) and with temperatures far below 0C. I
guess that weird blue/black cloud certainly was colder than all the
> On Fri, 7 Jun 2002, Louis wrote:
> You should check out the work of Trevor James Constable. He speaks of the
I just tried it again, this time with the driver side window AND the
windshield. They seem to have the same effect. Both block the "cold
fresh" feeling being sensed by my eyes.
I also tried stretching some Saran(tm) wrap across a metal hoop to form a
thin membrane window. This also works (it acts as a shield for the
"fresh" feeling of dark summer thunderclouds.)
On Sat, 8 Jun 2002, Nick Reiter wrote:
> The first was suggested to me by a friend at the lab, to whom I had
That sounds possible. But the effect seems more like a photocell
(reacting within a second or two.) Also, I don't have the same response
to UV-rich sunlight. However, that could involve psychology: my brain
interprets a "pure" source of the mystery-radiation differently than it
interprets a source accompanied by blinding visible light and IR.
> What other forms of known energy are blocked by glass / laminates as
> the hand or eyelids? Maybe someone has some ideas...millimeter waves?
> Long, soft X-rays?
If that kind of cloud has ice, it also has electrostatics. Maybe I'm
responding to an e-field? But it shouldn't be blocked by glass. Huh,
glass could block a DC field, since during humid days glass develops a
slightly damp coating.
It could be microwaves, but NEGATIVE microwaves. The entire 70F thermal
environment radiates microwaves as well as longwave IR. If a cloud has a
large region of -50F hail, it would be like a "hole" in the ambient
Experiment: cool the outside of a blimp with liquid nitrogen, then fly it
over my house. Will it "feel" the same way that the base of a
Thermal radiation is weird because it's separate from the air temperature.
You can be immersed in 70F air, but then stand ten feet from a window
which looks out on -20F winter. The window will seem to "radiate cold"
even though the air is actually warm. In fact, the warm walls of the room
are radiating IR, and the icy glass of the window is a "hole" in your
optical thermal environment.
Another idea: if this is an IR sense, and it only works when your eyes
are open, then maybe it will also detect WARM objects on cold winter days.
Unfortunately it's hard to separate it from normal vision. I can't close
my eyes since it blocks out both, hence I assume that I'm SEEING a warm
object, and I don't notice that another sensory channel is also operating.
I need to carry a pair of glasses around with me. They'd act like "closed
eyelids." Hey, if most people have this weird 6th sense, then those who
wear glasses will shut it off. DOes the world seem a bit different when
wearing glasses? I mean, apart from the change in blurryness. I think
I've noticed this too, but I put it down to the psychological effect of
occluding of peripheral vision. Does wearing lens-less glasses frames
"feel" different than wearing glasses with flat undistorting lenses? I
predict that it does.
Mammals with a visual "approaching storm detector" could know to head
across the fields to their burrows and not get caught out in a sudden
storm. If they could tell the difference between clouds of identical
coloration (dark stratus versus the dark base of a storm cell), so much
On Mon, 10 Jun 2002, Dean T. Miller wrote:
> We're probably talking about two different things. Really longwave IR
> probably needs waveguides. :) What wavelengths or frequencies do
> you suspect you're sensing?
I imagine that it's a "hole" in the sky's thermal glow, which otherwise
might be blackbody radiation for 40F or so (or whatever temperature the
non-thunderstorm cloud droplets had.)
> I would think that you'd get the same sensation when looking into a
> clear night sky, wouldn't you?
True, but I only notice the effect when it's relative to the rest of the
environment. But now that you mention it, I think you're right. A tree
or building seems different than the night sky. As with clouds, I always
assumed that this was just psychological (looking at familiar
"comfortable" trees and buildings, as opposed to the slightly frightening
unknown above.) But rather than comfortable versus frightning, I could
interpret it as warm versus cold. But it doesn't FEEL cold, not like skin
does. I think that's why it feels so strange. The warm objects don't
"look warm", instead they look "associated with comfort." And the cold
objects instead look "associated with danger." Whew, if I'm not just
fooling myself, this could be some kind of instinctual thing. "Seeing"
warm burrows and warm fellow creatures, versus looking into the cool
outside world which is full of threats. Or maybe it's some kind of
programmed response from infancy (optically detecting warm parents' bodies
versus cold dangerous world.) But doctor, I LIKE the infrared mommie.
Don't put me on the wire mommie anymore.
Hey, here's a product idea. What if your baby is crying because of fear,
because no IR-emitting parent is nearby? Erect a 98.5F heated panel
nearby the crib and within baby's visual field. Would human infants
respond to big warm blotches hovering over them?
I don't feel much of the effect from looking at the clear blue sky in
daytime, or from looking at cirrus clouds (which are ice crystals after
all.) When I was "feeling" that thunderstorm with my eyes, there was also
some blue sky and cirrus in the opposite direction, and they didn't have
the "feeling." But if it's truely caused by IR, maybe the glow from such
a thick layer of above-freezing air is enough to mask the missing glow
from cirrus clouds or from outer space? Or maybe I'm just responding to
thunderstorm orgone. :)
> The effective temperature is quite a
> bit below freezing (for almost all compounds, being close to absolute
I wonder what an IR spectrometer would think of the night sky. Does it
see space, or does it just see the glow from the miles thick of relatively
And about the freezer on my fridge, no dice. It's visually too small
unless I'm very close, and then I can feel cold air on my face. Also,
it's only 10F, probably much warmer than the descending ice in the storm.
End result: there might be a weak effect, but I can talk myself into
feeling it, or talk myself out of it, so I need some blind testing to be
sure. Compare a -50F white metal plate to a +32F white metal plate.
Ooo! I forgot the relative effect of the glass plate! I'll go try it
right now. Yes, I think it's actually there with the freezer. When I
look at the freezer and move the glass plate up and down, there's a change
in that "eye feeling", but when I do the same while looking at the kitchen
wall, the change is lots less. (But the change is there even with the
wall, although considerably smaller. Maybe the glass is reflecting IR
from my skin?)
Idea for art installation: three white metal plates mounted on the wall,
but each with a totally different blackbody radiation. Would they look
the same yet have different emotional impact? But how to keep ice and
condensation off the cold one? Ah, use a thin sheet of visibly opaque
IR-transparent plastic with the cold object mounted deep behind it. Hey,
maybe the plastic, if it's very thin, could even be made warm to the
touch, yet give off thermal radiation of "extreme cold."
I wish I had one of those noncontact IR thermometers you stick in your ear. Maybe the readings from that device would show that certain nearby clouds contain ice and others do not. I could extend its range; I've heard that polyethelene makes a good longwave IR lens and is easy to grind with a sander and polish with a torch. Or instead use a flashlight reflector with a thermistor at the focus. Make a bolometer.
An amazing device the bolometer;
Date: Wed, 12 Jun 2002 12:48:49 -0700 (PDT)
Now that I know what to look for, I *think* I'm "seeing" thermal IR all
over the place. But I haven't tried blind testing, so it could all be
just a matter of suggestion. Or maybe it's not IR at all. ANYWAY...
I refuse to believe that I'm special. If this is real, then nearly
everyone should have the sense. The effect is very strong with small
thunderstorms, but it arises in a couple of other places too.
Look at the image in a mirror. Now look at the image in a FRONT SURFACE
mirror. Isn't the image in the FS mirror much more lively and deep,
somehow more "savory" than the image in a normal glass mirror? I always
noticed this difference, but I put it down to psychological cues: there
is a slight double image in normal mirrors, and this tells us that the
mirror image isn't real. We learn as children that the world in a mirror
is an illusion, and we also learn how to recognize mirrors (by the slight
reflection from the glass.) Or so I always believed.
A Front Surface (FS) mirror is optically almost the same as a normal
mirror, the main
difference is that a normal mirror has a slab of glass in front of the
metal. Another difference: metal is a very good reflector of thermal IR,
and it is a terrible emitter. Silvered objects lose heat very slowly as
compared to other objects. If humans have a crude thermal-IR sense, then
we would "see" a polished metal surface as having an entire 3D infrared
world inside. The images in a FS mirror would look far more real because
they still have their IR cures. But a standard mirror would "look"
somewhat fake, like a warm object with images made of visible light alone.
Is that why cats ignore mirrors? Do they respond differently to FS
Another place where I think I see the effect: when viewing the outside
world through a closed glass window, versus viewing the world directly.
While driving, if I look at things through the windshield, they lack some
"liveliness." When I view things through the open dirver-side window,
the liveliness is restored. I always knew this, but I put it down to the
slight mistiness of dirty windows, or to the reflections that cue us to
the existence of the glass. But maybe it's caused by human IR sense.
One last musing: if infants rely on a 98.6F "mommy detector", then one
way to silence a crying baby might be to provide him/her with a nearby
warm object. If humans have an IR sense, then this warm object wouldn't
have to be in the crib, it only needs to be within view of the baby.