I've been thinking about infrared radiation and noticing more and more how the human skin seems actually pretty sensitive to it.
You can easily feel a bonfire from several meters away, far away from where any convection would heat your skin.
When you open the hood of your car you can feel the heat from the engine even standing back a step or two (away from the updraft of hot air).
Now try this: hold the palms of your hands against eachother a couple of inches apart and keep them like that for a couple of seconds. Then slowly (to avoid wind cooling) lift the other palm so they no longer face eachother. Do you feel it? For me there's a noticeable difference in warmth.
Is that the skin detecting black body radiation from other skin? This could be easily blind-tested with a friend; you hold your palm out and look the other way, then see if you can correctly tell when your friend's palm is near you palm and when its not. Maybe the human skin is even able to detect black body radiation from another human standing behind her? Kind of like a sixth sense. Could explain the sensation of "i knew someone was there".
I've noticed also that when you stand close to a concrete wall that was heated by the sun, but the sun has just set, you can tell which direction the wall is just from the heat on your body.
Is this all placebo or does it actually work that way?